CN114019638B - A kind of air-blown micro-cable, its preparation method and air-blown construction method - Google Patents

Abstract

The invention discloses an air-blown micro-cable, comprising a central reinforcing core, wherein the central reinforcing core is a hollow structure, and the inner cavity of the central reinforcing core serves as an air-blowing channel for air-blowing. The air-blown micro-cable of the present invention has the following advantages: 1) Under the condition of the air-blown micro-cable of the same structural size, the air-blown micro-cable of the present invention is lighter in weight. 2) The hollow structure of the central reinforcing core is adopted, and the air pressure is added from the central reinforcing core of the air-blown micro-cable. When the air is blown, it is subject to the traction force of the air flow in the central reinforcing core. The air blowing efficiency is high and the construction efficiency is high. 3) The air pressure can be applied to the inside and outside of the air-blown micro-cable at the same time for air blowing, and the air blowing distance is longer.

Description

A kind of air-blown micro-cable, its preparation method and air-blown construction method

technical field

The invention belongs to the field of optical cables, and more particularly, relates to an air-blown micro-cable, a preparation method thereof and an air-blown construction method.

Background technique

At present, with the development of my country's communication industry and the demand for mobile 5G construction, the demand for network capacity continues to increase. At the same time, urban land resources are increasingly scarce, and urban pipeline resources are becoming more and more tense. Therefore, it is urgent to increase the number of optical fiber cores in the limited pipeline and increase the optical fiber assembly density of the optical cable. Air-blown optical cable technology has become an important way to solve this problem. one.

Air-blown micro-cable is a kind of optical cable that can be laid by "air-blown" method. It has the advantages of high fiber density, small diameter, light weight and high air-blown laying efficiency. It has a wide range of applications, effectively saves pipeline resources, and meets the needs of network expansion and construction. With the popularity of the Internet and the demand for mobile Internet access, the amount of data transmission is increasing. The original small-core air-blown micro-cable can no longer meet the current demand. Micro-cable has the characteristics of heavy optical cable, short air blowing distance and low air blowing efficiency.

The outer diameter of the common GCYFY-144B1.3 optical cable is about 7.9mm, and the weight per kilometer is about 60KG/km. Under normal construction conditions, the cable is blown into a 12/10mm air blowing pipe, and the air blowing distance is usually about 1000. About meters (the length of the air blowing distance is related to the surface of the optical cable and the friction coefficient of the pipe, etc.), due to the large number of optical cable cores, the optical fiber connection will require more costs.

At present, the problems encountered in the actual development process of the air-blown micro-cable are: 1) The diameter of the central tube-type air-blown micro-cable is relatively large, and the duty ratio in the 5/3.5mm micro-tube (outside the cross-section of the micro-cable) The area of the edge / the area of the inner edge of the cross section of the microtube) is too high, which affects the air blowing effect; 2) The outer sheath of the central tube air-blown microcable is all high-density polyethylene HDPE, and its friction coefficient is from 0.12 to 0.35 It is mainly related to the choice of the grade of the sheath material and the processing technology of each manufacturer. Under the high duty cycle, it is difficult to have a better air blowing effect with such a friction coefficient. Therefore, some structures have central tube air blowing. In order to make up for the lack of friction coefficient of the micro-cable, some airflow channels are set on the surface of the sheath, which can objectively reduce the friction coefficient of the product. The blowing effect is not much improved, and it is difficult to make a big breakthrough in the air blowing distance, and it is difficult to meet the customer's requirements for long-distance air blowing and efficient construction. In the case of complicated construction routes and poor pipeline quality, it will affect the project. Progress; 3) When the air-blown micro-cable with HDPE as the sheath material rubs against the same material as the HDPE material as the air-blown pipe, the friction coefficient fluctuates greatly, which is reflected in the air-blowing effect that the air-blowing speed is unstable, which affects the air-blowing effect. Blow construction safety.

SUMMARY OF THE INVENTION

In view of the above defects or improvement needs of the prior art, the present invention provides an air-blown micro-cable, a preparation method thereof and an air-blown construction method, which can be simultaneously air-blown inside and outside, and the air-blowing distance becomes longer, which will reduce the number of connections. The workload is reduced, the construction cost is reduced, the efficiency is improved, and the air-blown distance of the air-blown micro-cable is effectively increased without changing the outer diameter of the air-blown micro-cable.

In order to achieve the above object, according to an aspect of the present invention, an air-blown microcable is provided, comprising a central reinforcing core, characterized in that the central reinforcing core is a hollow structure, and the inner cavity of the central reinforcing core serves as an air-blown microcable. channel for air blowing.

Preferably, the roughness of the inner wall of the central reinforcing core is greater than the roughness of the outer wall of the outer sheath of the air-blown microcable, so as to improve the traction force of the air-blown microcable.

Preferably, the inner space ratio of the central reinforcing core is 23% to 30%.

Preferably, it also includes a sealed bearing sleeved on one end of the outer sheath of the air-blown micro-cable and used to be installed on the air-blowing machine, and the inner cavity of the sealed bearing is communicated with the inner cavity of the central reinforcing core, so that The air blower blows air toward the inner cavity of the central reinforcing core.

Preferably, the central reinforcement core comprises a hollow core tube and a reinforcement member disposed on the tube wall of the core tube, the axial direction of the reinforcement member is consistent with the axial direction of the core tube, and the reinforcement member is convex out of the inner wall of the core tube and not beyond the outer wall of the core tube;

The outer edge of the cross-section of the core tube and the cross-section of the reinforcement are both circular, and the line connecting the centers of the cross-sections of the two reinforcements is denoted as l, and l passes through the outer edge of the cross-section of the core tube. The center of the circle.

According to another aspect of the present invention, there is also provided the preparation method of the air-blown micro-cable, characterized in that it comprises the following steps:

1) Production of central reinforcing core: The reinforcing pieces are respectively passed through the openings on the die core of the extruder head, and air is blown in the die core to form the inner cavity of the core tube, and the polymer material is on the outside of the die core. Flow and attach to the reinforcement to form a core tube, and the core tube and the reinforcement together form a hollow central reinforcement core;

2) Vacuum sizing: let the central reinforcing core pass through the vacuum sizing sleeve of the vacuum sizing device, and ensure that the outer diameter and ovality of the central reinforcing core meet the set requirements through the vacuum sizing sleeve, and then store the central reinforcing core disk in the first on a winding reel;

3) Optical cable sub-unit production: The optical fiber bundle is released from the second winding reel, and then enters the extruder after being coated with fiber paste. The extruder forms a sleeve and covers it on the optical fiber bundle. Optical cable sub-units, and then the optical cable sub-units are stored on the third spool;

4) Cable core production: The central reinforcing core is released from the first reel and a plurality of optical cable sub-units are released from the third reel, the water-blocking yarn is placed on the central reinforcing core, and the optical cable sub-units are twisted according to the setting The twisting pitch of the fiber optic cable is wrapped around the central reinforcing core, and the aramid yarn is wrapped on the optical cable subunit to form the cable core in this way, and the cable core coil is stored on the fourth spool;

5) Outer sheath production: The cable core that has passed the test is released from the fourth winding reel, the water-blocking yarn is placed on the cable core, and then the outer sheath wrapped around the cable core is formed by an extruder. The cores together form the air-blown microcable.

According to another aspect of the present invention, the air-blown construction method of the air-blown micro-cable is also provided, characterized in that it comprises the following steps:

1) The inner end and the outer end of the air-blown micro-cable stored on the spool are respectively released from the spool to set the length, and the outer end of the air-blown micro-cable is used to travel in the air-blown duct, The inner end of the air-blown micro-cable is provided with a sealed bearing;

2) Let the position of the sealed bearing extend beyond the end side plate of the I-shaped spool, then install the sealed bearing seal on the air blower, and make the centerline of the sealed bearing and the centerline of the I-shaped spool coaxially arranged;

3) The I-shaped spool is rotated to pay off the air-blown micro-cable. The air blown by the air-blower passes through the inner cavity of the sealed bearing and flows into the inner cavity of the central reinforcing core, thereby pushing the outer end of the air-blown micro-cable in the air. Travel inside the blowpipe.

Preferably, another air blowing machine is used to blow the outside of the air-blown micro-cable.

Preferably, a plug is installed at one end of the air blowing micro-cable that is used to extend into the air blowing pipe, so as to block the end of the central reinforcing core.

Preferably, the air pressure of the inner air blow of the central reinforcing core does not exceed 12 bar.

In general, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

1) The air-blown micro-cable of the present invention adopts a hollow structure for the central reinforcing core, and the outer diameter of the air-blown micro-cable does not change, resulting in a lighter weight of the air-blown micro-cable and the friction between the air-blown micro-cable and the air-blown pipe. Reduced, during the air blowing construction, the inner end of the air blowing micro-cable on the spool can apply air pressure to the inside of the central reinforcing core, which can achieve the effect of air blowing from the inside and help to increase its air blowing distance.

2) In the air-blown micro-cable of the present invention, one end of the air-blown micro-cable is provided with a plug. During the air-blowing process of blowing air to the interior of the central reinforcing core, the air-blown micro-cable is not only subjected to friction and thrust, but also the air-blown micro-cable. There is also the traction force of the plug at one end, so that during the air blowing process, especially in the place where the pipeline route turns, the air blowing micro-cable is easier to bend, so that the air blowing distance is longer and the air blowing efficiency is higher.

Description of drawings

Fig. 1 is the structural representation of the air-blown micro-cable of the present invention;

Fig. 2 is the schematic diagram that the air-blown micro-cable of the present invention is stored on the spool during air-blown construction;

Fig. 3 is the schematic diagram of the mold core used on the extruder in the preparation method of the air-blown microcable of the present invention;

In all the drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-strength; 2-central reinforcing core; 3-water blocking yarn; 4-fiber; 5-fiber paste; 6- Sleeve; 7-aramid yarn; 8-outer sheath; 101-winding reel; 102-sealed bearing; 103-air-blown microcable; 9-mould core; 91-opening.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

1 to 3, an air-blown micro-cable 103 includes an outer sheath 8, a central reinforcing core 2, an optical cable sub-unit and a water blocking yarn 3 arranged in the outer sheath 8, and a plurality of the optical cable sub-units are Arranged around the central reinforcing core 2 in a twisted manner, water blocking yarns 3 are respectively arranged on the central reinforcing core 2 and the optical cable subunit, and the central reinforcing core 2 includes a hollow core tube and a The two reinforcing members 1 on the tube wall of the core tube that are parallel to each other, preferably FRP strips are used for the reinforcing member 1, and the inner cavity of the core tube is used as an air blowing channel for air blowing. The axial direction of the reinforcement member 1 is consistent with the axial direction of the core tube. The reinforcement member 1 protrudes from the inner wall of the core tube and does not exceed the outer wall of the core tube. This structure can improve the central reinforcement core 2 The strength of the central reinforcing core 2 can withstand greater air pressure. The air-blown micro-cable 103 of the structure of the present invention adopts a hollow structure for the central reinforcing core 2, and the size of the air-blown micro-cable 103 does not change, resulting in a lighter weight of the air-blown micro-cable 103. The difference between the air-blown micro-cable 103 and the air-blown pipe friction between them is reduced.

The cross-section of the central reinforcing core 2 is a center-symmetric structure. For the cross-section of the core tube, its outer edge is a circle, and its inner edge has two arcs, and the ends of each arc are respectively connected with one arc. The cross-section of the reinforcement 1 is connected.

The cross-section of the reinforcing member 1 is circular, and the line connecting the centers of the cross-sections of the two reinforcing members 1 is denoted as l, where l passes through the center of the outer edge of the cross-section of the core tube.

The roughness of the inner wall of the central reinforcing core 2 is greater than the roughness of the outer wall of the outer sheath 8, so as to improve the traction force of the air blowing.

The inner space ratio of the central reinforcing core 2 (it can be considered as the area of the inner edge of the cross-section of the central reinforcing core 2/the area of the outer edge of the cross-section of the central reinforcing core 2) is 23% to 30%, so that the inner space of the central reinforcing core 2 is 23% to 30%. The cavity forms a sufficiently high air pressure, and the air pressure blown from the inside of the central reinforcing core 2 can reach a maximum of 12 bar.

Generally, the friction coefficient of the air-blown micro-cable 103 relative to the imported silicon core tube is 0.05-0.07. In order to increase the traction force of the air blowing in the central reinforcing core 2, the material properties are changed during the production of the central reinforcing core 2, so that the inner wall of the central reinforcing core 2 is rubbed. coefficient is relatively large. The friction coefficient is a relative value. The friction coefficient of the surface of the air-blown micro-cable 103 is a relative value between the surface of the air-blown micro-cable 103 and the silicon core tube. That is, the inner wall of the central reinforcing core 2 is rougher than the outer surface of the outer sheath 8, and the roughness is larger.

In view of the situation where the air-blown micro-cable 103 is coiled and stored on the spool for air blowing, the 8 end of the outer sheath of the air-blown micro-cable 103 is also sheathed with a sealed bearing for installation on the air blower. The cavity communicates with the inner cavity of the central reinforcing core 2 , so that the air blower blows air toward the inner cavity of the central reinforcing core 2 . The air blower can blow air toward the inner cavity of the sealed bearing, and the air flow will also enter the inner cavity of the central reinforcing core 2, so that the air-blown micro-cable can be pushed to travel in the air-blown duct.

According to another aspect of the present invention, a method for preparing the air-blown micro-cable 103 is also provided, comprising the following steps:

1) Production of the central reinforcing core 2: each reinforcing piece 1 is passed through an opening 91 on the die core 9 of the extruder head, and the two FRP strips are placed symmetrically at 180 degrees, and air is blown in the die core 9. In order to form the inner cavity of the core tube, the polymer material flows on the outside of the mold core 9 and is attached to the two reinforcing members 1 to form the core tube, and the core tube and the two reinforcing members 1 together form the hollow central reinforcing core. 2. The polymer material is preferably PE material.

2) Vacuum sizing: let the central reinforcing core 2 pass through the vacuum sizing sleeve of the vacuum sizing device, and ensure that the outer diameter and ovality of the central reinforcing core 2 meet the set requirements through the vacuum sizing sleeve, and the outer diameter of the central reinforcing core 2 is 4.1mm, and the ovality is generally less than 5%. The wall thickness of the central reinforcing core 2 produced by this process is about 0.5mm-0.6mm. The central reinforcement core 2 is then reeled onto the first spool.

3) Optical cable sub-unit production: the optical fiber bundle 4 is released from the second winding reel, and after coating the fiber paste 5, it enters the extruder, and the extruder shapes the sleeve 6 and sets it on the optical fiber bundle 4. 5 and the optical fiber bundle 4 together form an optical cable sub-unit, and then the optical cable sub-unit is stored on the third reel; the sleeve 6 of the optical cable sub-unit adopts PBT material or TPEE material, and the sleeve 6 is filled with thixotropic fibers The paste 5 not only protects the optical fiber, but also ensures the waterproof performance of the sleeve 6 . The outer diameter of the sleeve 6 is controlled at 1.42mm-1.5mm, the excess length of the optical fiber is controlled at ±0.02% through the twisting process, the wall thickness of the sleeve 6 is controlled at 0.1mm-0.15mm, and the sleeve 6 can be tested after passing the test. Production of cable cores.

4) Cable core production: The central reinforcing core 2 is released from the first reel and a plurality of optical cable sub-units are released from the third reel. Release, put the water blocking yarn 3 on the central reinforcing core 2, preferably one ZS-10.0 water blocking yarn 3 is wound on the central reinforcing core 2 and placed directly on the central reinforcing core 2, and the optical cable sub-unit is twisted according to the set twist. It is wrapped around the central reinforcing core 2 at a certain pitch, and the aramid yarn 7 is covered on the optical cable sub-unit. It is preferable to fix the optical cable sub-unit by two aramid yarns 7 with a specification of 1500D (1670 Dtex), and the tension of the aramid yarn 7 is as far as possible. The cable core is formed in this way, and the cable core is stored on the fourth winding reel; the yarn is wound with a flying shuttle, which ensures the waterproofness of the optical cable sub-unit and the central reinforcing core 2. performance.

5) Production of outer sheath 8: the cable core that has passed the test is released from the fourth winding reel, and the water-blocking yarn 3 is placed on the cable core. Then, the outer sheath 8 wrapped around the cable core is formed by an extruder, and the outer sheath 8 and the cable core together form the air-blown micro-cable 103; the outer sheath 8 adopts Borealis with a small friction coefficient HDPE6069.

The production of the air-blown micro-cable 103 is completed through the above steps. The air-blown micro-cable 103 produced by this process is light in weight, long in air-blowing distance and high in air-blowing efficiency. Through the comparison test of the produced air-blown micro-cable 103, it is found that The air blowing distance of the air-blown micro-cable 103 of this structure is 50% longer than that of the traditional optical cable. Under the same air-blowing condition, the air-blowing speed is faster, and the air-blown micro-cable of the same length will save 30% of the time. The air-blown micro-cable 103 produced by the invention provides convenience for construction and improves the efficiency of air-blown construction.

According to another aspect of the present invention, the air-blown construction method of the air-blown micro-cable 103 is also provided, comprising the following steps:

1) The inner and outer ends of the air-blown micro-cable 103 stored on the winding reel (the two ends of the air-blown micro-cable 103 are divided into an inner end and an outer end, the outer end can be paid out freely, and the inner end cannot. Free pay-off) are respectively released from the spool for a set length, the outer end of the air-blown micro-cable 103 is used to travel in the air-blown pipe, and the inner end of the air-blown micro-cable 103 is installed with a sealed bearing 102 . The length of the air-blown microcable 103 released from the inner end is about 2 meters.

2) Let the position of the sealed bearing 102 extend beyond the end side plate of the I-shaped reel 101 (the I-shaped reel 101 has a middle cylinder and end side plates arranged at both ends of the middle cylinder, and the middle cylinder is used for winding , pay off), and then seal the sealed bearing 102 installed on the air blower, and make the center line of the sealed bearing 102 and the center line of the I-shaped spool 101 coaxially arranged. The section of the air-blown micro-cable 103 where the sealed bearing 102 is installed can be fixed on the end side plate of the I-shaped spool 101 through a tube clamp to prevent the I-shaped spool 101 from swinging when the I-shaped spool 101 rotates; To bear the torsional force has an effect on the optical fiber, and can eventually be removed.

3) The I-shaped spool 101 is rotated to pay off the air-blown micro-cable 103, and the air-blower blows air into the inner cavity of the central reinforcing core 2 to push the outer end of the air-blown micro-cable 103 to travel in the air-blown pipe. At the same time, optionally, another air blower is also used for air blowing on the outside of the air blowing micro-cable 103, so that the air blowing micro-cable 103 can be blown inside and outside, so as to improve the air blowing efficiency, and the air blowing The air pressure inside the central reinforcing core 2 of the cable 103 is preferably lower than the air pressure outside the outer sheath 8, which effectively prevents the air-blown micro-cable 103 from shaking in the air-blown pipe. When the inner end of the air-blown micro-cable 103 is blown and paid out, since the I-shaped spool 101 is also rotating at the same time, the air-blown micro-cable 103 will also be carried by the I-shaped spool 101 to rotate together, sealing the bearing 102 It can ensure that the inner end of the air-blown micro-cable 103 rotates synchronously by de-twisting, and does not affect the air-blower to pressurize the interior of the central reinforcing core 2 . In addition, a plug is installed at one end of the air-blown micro-cable 103 that is used to extend into the air-blowing pipe, so as to block the end of the central reinforcing core 2, then during the air-blowing process, the air-blown micro-cable 103 is not only affected by Friction and thrust, one end of the air blowing micro-cable 103 also has the traction force of the plug, so that during the air blowing process, especially in the place where the air blowing pipe turns, the air blowing micro-cable 103 is easier to bend, so that the air blowing distance Farther, the air blowing efficiency is higher. Of course, from the perspective of safety, it is not necessary to use a plug to seal, and internal air blowing can also be achieved.

Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, etc., All should be included within the protection scope of the present invention.

Claims (9)

1. An air-blowing micro cable, comprising a central reinforcing core (2), characterized in that the central reinforcing core (2) is of a hollow structure, and the inner cavity of the central reinforcing core (2) is used as an air-blowing channel for air-blowing; the roughness of the inner wall of the central reinforcing core (2) is larger than that of the outer wall of the outer sheath (8) of the air-blowing micro cable, so that the air-blowing traction force is improved.

2. An air-blown micro-cable according to claim 1, wherein the hollow proportion of said central reinforcing core (2) is 23% to 30%.

3. An air-blowing micro-cable according to claim 1, further comprising a sealing bearing sleeved at one end of the outer sheath of the air-blowing micro-cable for mounting to an air-blowing machine, the inner cavity of the sealing bearing being in communication with the inner cavity of the central reinforcing core (2) so that the air-blowing machine blows air towards the inner cavity of the central reinforcing core (2).

4. A gas-blown micro cable according to claim 1, wherein the central reinforcing core (2) comprises a hollow core tube and a reinforcing member (1) provided on a wall of the core tube, an axial direction of the reinforcing member (1) being coincident with an axial direction of the core tube, the reinforcing member (1) protruding from an inner wall of the core tube and not exceeding an outer wall of the core tube;

the outer edge of the cross section of the core tube and the cross section of the reinforcing piece (1) are both circular, the connecting line of the circle centers of the cross sections of the two reinforcing pieces (1) is marked as l, and the l passes through the circle center of the outer edge of the cross section of the core tube.

5. A method of making an air-blown micro-cable according to any one of claims 1 to 4, comprising the steps of:

1) production of the central reinforcing core (2): respectively enabling the reinforcing parts (1) to pass through openings (91) on a mold core (9) of a machine head of an extruding machine, blowing air into the mold core (9) to form an inner cavity of a core pipe, enabling the high polymer material to flow outside the mold core (9) and be attached to the reinforcing parts (1) to form the core pipe, and enabling the core pipe and the reinforcing parts (1) to form a hollow central reinforcing core (2);

2) vacuum sizing: the central reinforcing core (2) passes through a vacuum sizing sleeve of a vacuum sizing device, the outer diameter and the ovality of the central reinforcing core (2) are guaranteed to meet set requirements through the vacuum sizing sleeve, and then the central reinforcing core (2) is wound on a first wire winding disc;

3) and (3) optical cable subunit production: the optical fiber bundle (4) is discharged from the second wire spool, the optical fiber bundle enters an extruding machine after being coated with the fiber paste (5), a sleeve (6) formed by the extruding machine is sleeved on the optical fiber bundle (4), the sleeve (6), the fiber paste (5) and the optical fiber bundle (4) jointly form an optical cable subunit, and then the optical cable subunit is coiled on a third wire spool;

4) cable core production: the central reinforced core (2) is paid out from the first wire reel and the optical cable subunits are paid out from the third wire reel, the water-blocking yarn (3) is paid out from the central reinforced core (2), the optical cable subunits are wrapped around the central reinforced core (2) according to the set stranding pitch in a stranding mode, the aramid yarn (7) is wrapped on the optical cable subunits, in this way, a cable core is formed, and the cable core is stored on the fourth wire reel;

5) production of the outer sheath (8): and the cable core qualified in test is discharged from the fourth wire spool, the water-blocking yarn (3) is placed on the cable core, then an outer sheath (8) coated around the cable core is formed by a plastic extruding machine, and the outer sheath (8) and the cable core jointly form the air-blowing micro cable.

6. The air-blowing construction method of the air-blowing micro cable according to any one of claims 1 to 4, comprising the steps of:

1) respectively discharging the inner end and the outer end of an air-blowing micro cable (103) which is stored on a wire spool to set lengths from the wire spool, wherein the outer end of the air-blowing micro cable (103) is used for advancing in an air-blowing pipeline, and the inner end of the air-blowing micro cable (103) is provided with a sealing bearing (102);

2) the position of the sealing bearing (102) exceeds the end side plate of the I-shaped wire spool (101), then the sealing bearing (102) is hermetically installed on the air blowing machine, and the central line of the sealing bearing (102) and the central line of the I-shaped wire spool (101) are coaxially arranged;

3) the I-shaped wire spool (101) rotates to pay off the air-blowing micro cable (103), and air flow blown out by the air-blowing machine flows into the inner cavity of the central reinforcing core (2) after passing through the inner cavity of the sealing bearing (102), so that the outer end of the air-blowing micro cable (103) is pushed to advance in an air-blowing pipeline.

7. The air-blowing construction method of the air-blowing micro cable according to claim 6, wherein the outside of the air-blowing micro cable (103) is also air-blown by another air-blowing machine.

8. The air-blowing construction method of the air-blowing micro cable according to claim 6, wherein a plug is installed at one end of the air-blowing micro cable (103) for extending into an air-blowing pipeline, so as to plug the end of the central reinforcing core (2).

9. The air-blowing construction method of an air-blowing micro cable as claimed in claim 6, wherein the air pressure of the air-blowing inside the central reinforcing core (2) is not more than 12 bar.

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