Blast furnace top charging equipment · Bell-less top with intermediate hoppers, sealing and isolation valves, material flow control, rotating and tilting distribution chute, burden profiles and centre coke charging, drive maintenance and retrofit
A blast furnace top charging system receives ore, coke and fluxes at the top of the furnace and places them inside in controlled layers while keeping the pressurised furnace gas in. A bell-less top, which US 4,322,197 calls "one of the most significant recent advances in blast furnace technology", works as follows: hoppers that are pressure-locked by valves feed a central chute and a rotating, tilting distribution chute that sets where each batch lands. Ask three things first: what furnace size and charging rate it must serve, how the hoppers and valves lock in furnace pressure, and how the chute drive is controlled and maintained.
Top charging installations for blast furnaces and other shaft furnaces, especially bell-less tops with intermediate hoppers, flow control and isolation valves, central feed channels, distribution chutes and their drives. Conventional bell-type tops are compared; stock-house conveying, skip hoists, top gas cleaning and the furnace shell are outside this page.
CNFX editorial research · Sources checked October 12, 2026 · 4 sources
US patent 4,322,197 (Process and installation for charging a shaft furnace) describes the bell-less top as "one of the most significant recent advances in blast furnace technology": a rotary, angularly adjustable distribution chute supplied from a pair of intermediate storage hoppers, which allows charging to be controlled more accurately than with bell-type devices and so lets furnace output be optimised. The paired hoppers are alternately connected to the furnace through a material flow control (dosing) valve, and isolation valves at both their feed and discharge ends are needed because each hopper must be at atmospheric pressure for loading and at furnace pressure for discharging; with two hoppers, charging is almost continuous, interrupted only while the isolation valves open and close. The patent proposes a single-hopper installation to make the bell-less top affordable for small and medium furnaces and retrofits. [1]
US patent 4,138,022 (Furnace top charging apparatus) describes a conventional bell-less arrangement in which two bunkers are filled alternately through switching chutes with exhaust ports and raw material control gates, swingable sealing valves in the collecting chute prevent gas leakage during charging, and material passes through the collecting chute, a vertical chute in the rotating drive chamber and the rotating distribution chute into the furnace. [2]
Editorial note: give the supplier the furnace top pressure, the batch sizes and number of batches per hour, and whether you want parallel or single-hopper arrangement, so it can size hoppers, valves and equalising.
Give the supplier the furnace working volume and top pressure, raw materials and batch sizes, charging rate, hopper arrangement (parallel, central, single), valve types and pressure equalising and relief, distribution chute length and tilt range, rotation and tilt drive, burden profile control and measurement, cooling of the drive, existing structure for retrofit, crane and maintenance access, and automation interface.
02
Choose serial or parallel hoppers
Qinhuangdao Qinye Heavy Industry, a Chinese maker of bell-less top equipment, describes two hopper layouts on its product page. In a serial (串罐) top the upper seal valve, the hopper and the material flow control valve are stacked one above the other, with the receiving hopper and the pressurised hopper on the furnace centreline; the maker states this distributes burden without the segregation that comes from an off-centre hopper, makes the top-gas profile easier to hold to the ironmaking requirement, and takes less space on the top platform than a parallel top for a furnace of the same working volume. In a parallel (并罐) top two sets of upper seal valve, hopper and flow control valve sit symmetrically about the centreline and work alternately, one charging the furnace while the other is filled, which the maker says gives more capacity to catch up the stock line than a serial top. [4]
Qinye states that, with Baosteel and CISDI, it developed a bell-less top for furnaces of the 5000 m³ class from 2009, and that it can now design and build complete bell-less tops for furnaces up to that class. Its reference list for serial tops names furnaces of 5050 m³ (Baosteel Zhanjiang), 2500 m³, 2000 m³, 1780 m³ and 1680 m³ and gives more than 100 furnaces in total; for parallel tops it names furnaces of 4350 m³, 4150 m³, 3800 m³, 2550 m³ and 1650 m³. [4] It describes the lower valve box as combining the lower seal valve and the flow control valve, and the distributor (gas-tight box) as rotating and tilting the chute for ring, spiral, spot, sector and centre-coke charging. [4]
Editorial note: these are the maker's own reference claims; ask any bidder for a reference furnace of similar working volume and the same hopper layout, and compare the alternating two-hopper cycle described in US 4,322,197 with the serial layout before fixing the top platform design. [4][1]
Layout
Arrangement
Stated advantage
Furnace volumes named by the maker
Serial (串罐)
Seal valve, hopper and flow control valve stacked on the centreline [4]
No off-centre segregation; smaller platform footprint [4]
Specify the distribution chute, drive and maintenance
US patent 7,909,556 B2 (Charging device and distribution chute for a shaft furnace) states that bell-less charging devices have found widespread use for decades: charge is discharged from a hopper through a central feed channel onto a distribution chute, which the drive rotates about a vertical axis and pivots about a horizontal axis, so any desired charge profile can be laid on the burden surface. It notes that a central coke chimney, made by pivoting the chute to a central charging position, increases draft and feeds coarse coke to the centre to improve permeability of the dead man, and the chute must then not intercept the central flow. [3]
US 4,138,022 explains that the vertical chute wears severely and the rotating drive chamber is prone to faults, so "they are often taken out of the furnace for periodic inspection and also due to breakdowns"; the drive chamber is "very heavy (in general more than 30 tons)" and, with surrounding support beams, removal by winch is slow, laborious and costly in downtime. Its design aims to make removal easier. [2]
Editorial note: ask the supplier how the chute and drive are lifted out, the expected chute liner life, and the downtime for a chute change on your furnace.
04
Intermediate hoppers, isolation and sealing valves, dosing valve, feed channel, distribution chute and drive chamber
The drive chamber row carries the maintenance burden: US 4,138,022 describes the chamber as heavy and prone to faults and taken out for inspection and after breakdowns, so its removal method belongs in the order. [2]
Charge rate, top pressure, valve sealing, hopper volume, drive and lifting weights for a top charging order
The sources give no numeric rating for these fields beyond the drive chamber's weight of more than 30 t; temperature, drive power, control voltage, IP rating and material grades have to come from the bidder. [2]
Field
What it means and published values
Ask the supplier for
Charging Capacity (t/h)
Batches per hour; near-continuous with two hoppers. [1]
1 company lists this product among what they make. Company figures are quoted from each
company's own website; every card states where the relationship came from.
Qinhuangdao Qinye Heavy Industry Co., Ltd.
Manufacturing site to be confirmed for the order
Its website lists bell-less blast furnace top equipment.
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
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Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 13 October 2026
Buyer questions
What is a bell-less top?
A charging installation with a rotating, tilting distribution chute fed from intermediate hoppers, giving more accurate burden control than bells (US 4,322,197). [1]
Why do the hoppers need isolation valves?
Each hopper alternates between atmospheric pressure for loading and furnace pressure for discharging (US 4,322,197). [1]
What is centre coke charging?
Pivoting the chute to a central position to form a coke chimney that increases draft and dead-man permeability (US 7,909,556). [3]
What is the difference between a serial and a parallel bell-less top?
Qinye describes a serial top as having the hoppers stacked on the furnace centreline, avoiding off-centre segregation and saving platform space, and a parallel top as two hoppers working alternately, which recovers the stock line faster. [4]
Sources and what still needs a direct check
Sources checked 2026-10-12. Three sources are US patents describing bell-less top charging in their own terms; the fourth is a Chinese maker's product page describing its serial and parallel tops and its own reference furnaces.
