Techical arrangement characteristics:
1、Reasonable structural design ensures good service performance.  The performance parameters of the blast furnace intake air-delivery device together with the product quality can satisfy the service requirements of large- & medium-sized blast furnaces and powerfully ensure the blast furnace smelting under high blast-temperature, high top-pressure and high strength.  Compared with structural form of the original blast furnace intake air-delivery device, this air-delivery device has the following features:
2、 Good heat durability; withstanding high blast-temperature up to 1400℃.
3、Step-type structure is adopted for the internal hot blast passage, with good airtightness at all the joints; withstanding 1.25 times of the work pressure.High number of fatigue-resistant times; long service life; the work temperature on the exterior of the expander is kept between 100～150℃; the expander is of good mechanical properties.

4、Wide range (8⁰~14⁰) of the choice of the angle for inserting the blast gun; help to raise the combustion rate of the coal dust.Big radial and azimuthal compensation amount; a float-sealing-type structure is adopted at the connection of the fire-proof internal lining, enabling self-adjusting of the displacement under the conditions of heat-expansion and cold-contraction for 20~50 mm in radial direction and for 3~6⁰ in azimuth.

5、Easy & convenient installation and adjustment.  Four tie-bars are used for the connection between the air-intake branch-pipe and the outside of the expander to facilitate the adjustment of the expander by tensioning the tie-bars and to facilitate the installation and adjustment of such structural equipment as the belly pipe, the branch pipe, etc.Good thermo insulating property and low heat loss.  The fire-proof lining is made by casting of the fireproof material, of which the proportioning is self-developed by the company, and has undergone repeated experiments and practice proof-tests.  The outer shell temperature can be below 200℃; the expander’s temperature reaches 100～150℃; thus the heat loss is reduced, the temperature of the intake hot blast is raised, and the operational environment in front of the furnace is improved.

6、The function of the blast intake device is to deliver the hot blast from the hot blast bustle pipe into the crucible of the blast furnace and then blow the fuel into the blast furnace by means of this device.
By means of the relative angle deflection distortion of the corrugated pipe expansion joint, this device absorbs the displacement caused by the thermal expansion of the blast branch-pipe system.  The relatively reasonable structure of all the components ensure the good performance of the entire operation.  The adoption of overseas advanced technology and process for the casting & roasting of the blast intake cast-resisting material, the normal operational periodicity is prolonged, which ensures no stripping-off at such weak position as coal-jetting connection.  At the same time, the outer shell temperature of the blast branch-pipe system is lowered and the operational environment for the blast furnace operator is improved correspondingly.
Technical Properties
· High pressure endurance:  good airtightness, small pressure loss, capable of enduring the work pressure of 0.2-0.67MPa without air leakage.
· Good heat endurance:  capable of enduring the high blast temperature of 1000-1400℃, with low surface temperature and low heat loss.
· Good fatigue resistance:  long service life; good mechanical property of the expander under the hot-expansion & cold-contraction conditions; displacement in any direction within a range of 12 mm can be realized; service life being 1~4 years; long replacement cycle; downtime percentage reduced.