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Water descaling unit
for rolling mill

Engineering company ENCE GmbH (ЭНЦЕ ГмбХ) offers various units, complete sections and associated equipment for the rolling mills, hot-dip galvanizing lines coiled steel, strip color and polymeric coating lines, automatic pickling lines for steel strip as well as sheet-bending machines. For instance, company ENCE GmbH (ЭНЦЕ ГмбХ) предлагает offers to develop water descaling units as per the technical requirements of the customer. These units are widely used in the manufacturing process after reheating furnaces,as well as before and after mill rolling stands.

As an example,Company ENCE GmbH (ЭНЦЕ ГмбХ) offers one of the template solutions for water descaling units. This solution has been developed for the mill 2800, according to the following initial data.

MODEL 1

INITIAL DATA AND DESCALING UNIT CHARACTERISTICS:

Slab dimensions Accumulator flow rate Pressure Weight/pce. Q-ty Pcs./hr Time
240 х 1600 x 3250 mm 73,8 m³/h Max. 30 MPa 9700 kg Up to 36 100 s
240 x 1600 x 1020 mm 23,8 m³/h Max. 30 MPa 3129 kg Up to 36 30 s

Descaling roller table speed: 1,5 m/sec after the reheating furnace
1,8 m/sec 1st system of mill nozzles
2,0 m/sec 2nd system of mill nozzles
4,0 m/sec 3rd system of mill nozzles

Feed sequence: 36 pcs./hour

Signal source: from the existing unit (4…20mA, 0…10 V DC)

Product length: max. 3220 mm @ 1150 – 1170 °C after the furnace
max. 23000 mm @ 950 -1000 °C after rolling

Slab size tolerance:

  • length – 0/+25 mm;
  • width – minus 5/+10 mm;
  • thickness – minus 3/+3 mm;
  • size difference of wide edges – max. 10 mm;
  • camber per 1 running meter of slab length – ≤4 mm;
  • side strain (camber to the side) of the wide edge – ≤2 mm;
  • side strain (camber to the side) of the narrow edge – ≤4 mm;
  • rhombic form (diagonal difference) of the slab cross-section – ≤5 mm;
  • trapezoidal section (difference between the sized of wide edges) – ≤6 mm;
  • cutting angle – ≤10 мм;
  • flatness deviation per 1 m – ≤4 mm.

Steel grades: as per the technical requirements

Descaling cycle time: as per the actual slab length

Water descaling unit is designed for continuous working mode as per the requirements of the Customer.

Furnace operation:
Compressed air feed:
Water supply:






Electric power:
For the pumping station
For compressordrive
Solid waste
slab heating
0,63 MPa, 50 liters per minute (cry clean air)
min. 0.6 MPa at filter inlet, constant
Total consumption max. 120 m33/hour
Salt total content max. 250 mg/l
Chlorides: max. 200 mg/l
Sulphates: max. 200 mg/l
Nontransferrin-bound iron: no
Free oxygen: no
380 V, 50 Hz, AC 3 phase
4 x 250 kW, 1 x 250 kW standby
1 х 45 kW
Descaling and scale removal
Customer’s responsibility


WATER DESCALING UNIT DESCRIPTION

Water descaling unit for rolling mill

Water descaling unit includes the following items:

  • Automatic backwashfilter 160 m³3/hour, filtering element SS 100 µm, digitally controlled, with welded counter flanges
  • Pumping station with total discharge pressure 300 bar, consists of four main and one standby triplex plunger pumps (flow rate 340 l/min, discharge pressure 33 MPa). Plunger pumps comprise the following:
    • Ceramic plungers,
    • pressure lubricating system, including in-built gear box and cooling,
    • safety relief valve,
    • 250 kW motor, 1500 rpm,
    • High torque couple,
    • High pressure pulsation damper at suction side,
    • High pressureentry shutoff valve,
    • Base frame,
    • Pressure relay at pump suction side,
    • check valve,
    • High speed unloading machine,
    • IP55 junction box with built-in monitoring of:
      • Low water pressure,
      • Low lubrication oil pressure
      • High lubrication oil temperature.
  • Pressure gauge with design parameters 63 MPa with pulsation damper
  • Low pressure pipeline made of carbon steel; fittings, shutoff and adjustment valves for high pressure pumping station / filter
  • High pressure pipeline made of special steel and high pressure pump fittings for flanged scale accumulator. Limited by pipeline path length of 50 m.
  • Vertical accumulator tank with rated pressure = 32 MPa, height = approx. 4 m, with pressure and water level control and safety relief valve (full volume = 20 m3)
  • High pressure air compressor 32 MPa, 1000 l/min, complete with high pressure piping to the accumulator tank
  • Safety shutdown valve (solenoid type), manual isolationvalve for accumulator tank operation, complete with bypass filling valve
  • Descaling system on/off valve (24 V DC) with in-built system of valve filling for an injection ring in order to avoid hydraulic shock during unloading mode, protective device
  • Scale collecting box, with upper and lower nozzles manifold, sector control for slab width adjustment (1600 or 2570 mm), installed after the furnace, approx. length 3500 mm,
  • Upper part material – low carbon steel,
  • Lower part material – stainless steel,
  • Liner for transportation of the removed scale to the box
  • Gripping device
  • Special sealing for the rolls
  • Multi-stage curtain at the entry and exit,
  • Nozzles manifold, installed on the unit with automatic height adjustment, water descaling nozzles with inserts to avoid undesirable heating
  • High-pressure water hoses from the descaling valve to the manifold
  • Monitoring and control center for pump motors (5 hp), as well as compressor, power relay, IP 55, switchbox with 100 mm grated floor, water descaling unit control,
  • Control panel: LCD-display 4-line screen, power supply 24 V DC, lamps, IP55 to be located in the control room, mode: automatic/manual
  • Local control panel located near the pump for start and shutdown of 5 pumps and filter control, complete with local remote selector switch located beside the high-pressure pumping station

All the components are painted and protected against corrosion as per DIN EN ISO 12944, C3.

Water descaling unit is designed for max. allowable unevenness=10 mm in order to avoid formation of the strips where the scale have not been removed.

High-pressure pumping station recharges the high-pressure accumulator tank designed for storing feed-water. Accumulator station is complete with a shutoff valve, an air pressure relief valve, manual isolation valve (for maintenance only) and pressure control system. High-pressure piping will be made of pipe steel, in order to connect pipe flow to the valves for descaling and complete with heavy-duty PP clamps, fittings, hoses, etc. Descaling speed on the liner = 1.5-4 m/sec. Water descaling unit operates according to the required rolling speed/ mill capacity



MODEL 2

INITIAL DATA AND DESCALING UNIT CHARACTERISTICS:

Ingot size, mm Water flow rate, m³/hour Pressure, MPa Scale type Q-tyPcs./hour
140 х 140 1200 - 3100 40,0 25,0 Furnace scale 60
170 х 170 40,0 25,0 Furnace scale 120
Descaling roller table speed:
Feed sequence:
1,0 – 2,0 m/sec
60 -120 pcs./hour

Signal source: from the existing plant (4…20mA, 24 V DC)

Furnace temperature:
Furnace operation:
1180 ± 20 °C
ingot heating

Steel grades: as per the technical requirements

Water descaling system is designed for continuous working mode as per the requirements of the Customer.

Compressed air supply:
Water supply:








Electric power:
For the pumping station
Control voltage
Solid waste
0,6 MPa, (dry and clean air)
min. 0.4 – max. 0.6 MPa at the inlet, constant
Total consumption max. 40 m3/hour
Temperature = approx. 30 °C
РН value approx. 7
Total salt content max. 500 mg/l
Chlorides: mac. 150 mg/l
Sulphates: max. 150 mg/l
Nontransferrin-bound iron: no
Free oxygen: no
400 V , 50 Hz, AC 3 phase
3 x 160 kW, 1 x 160 kW standby
220 V, alternating / 24V, directcurrent
descaling and scale removal
Customer’s responsibility

Water descaling unit for rolling mill


WATER DESCALING UNIT CONSISTS OF THE FOLLOWING COMPONENTS:

  • Pumping station
    • 3 operating three plunger pumps and 1 standby pump. Each pump has the following characteristics:
      • Operating pressure - 250 bar
      • Flow rate- 13,2 m3/hour (220 l/min)
      • Power - 160 kW
    • Pump accessories:
      • V-belt drive
      • Belt guard
      • E-motor
      • Pneumatic system of suction valves for loading/unloading of the feed unit
      • Manometer
      • safety relief valve
      • Pulsation damper on the pump suction line
      • Compensator and manual shutoff valve on the pump suction line
      • Pressure relay on the pump suction line
      • Ball valve on the pump discharge line
      • High-pressure hose on the pumps’suction line
      • High-pressure hose on the pumps’discharge line
      • High-pressure check valve on the pump discharge line
      • Junction box
      • Base frame with control panel
  • Water treatment unit on the pumping station suction line
    • Self-cleaning automatic filter
    • Water intake and treatment device with a pulsation damper
    • Boost pump (flow rate – 40 - 45 m3/hour, 4-6 bar, 15 kW) complete with:
    • Motor
    • Standby pump
    • Manual shutoff valve on the suction line of the pumping unit
    • Check valve on the pumps’discharge line
  • Water descaling unit for rolling mill
  • Resonator for extinguishing of discharge pulsations (residual pulsation approx. 3-5%), including:
    • Connecting pipes
    • Base frame for resonator installation
  • Distributing assembly for water descaling unit
    • Distributing circuit
    • 12 spray nozzles, guidance tolerance during descaling ±15 mm/m
  • Electrical switch box and control panel of water descaling unit
    • Load dropping device
    • Star-delta combination 160 kW
    • Star-delta combination 15 kW
    • Automatic reverse in-line filtercontrol
    • Frequency converter (three pcs.) for water flow control at the outlet of the pumping station
    • Overload engine protection system
    • Pressure sensor for pressure control at the water descaling unit
    • HMD (hot metal detector) for ingot positioning
    • HMD (hot metal detector) for temperature measurement

Warranty is provided for the period of 12 months after commissioning, but not to exceed 18 months after the delivery.

Technical data package for the water descaling unit:

  • dimensional drawings of the descaling unit
  • foundation plan of the descaling unit
  • pump dimensional drawing, pump cross-section drawing,
  • layout of hydraulic components with pipe sizes,
  • distributive unit scheme with a distributive circuit and pump / piping locations,
  • description of the water descaling unit
  • maintenance & operation manual in Russian
  • water descaling unit test reports

Engineering company ENCE GmbH (ЭНЦЕ ГмбХ) also offers the following special equipment for processing and packing of the milled products, as well as components and replacement assemblies for the rolling mills:


ENCE GmbH, Switzerland / ENCE gmbH, Schweiz / ЭНЦЕ ГмбХ, Швейцария © ENCE GmbH