Medium Sized Electric Trolley Car Bottom Furnaces,  Heat Treating Furnace

1. Overview

  This electric heat treatment furnace is a car bottom furnace, which is mainly used for stress relief, annealing and heating of metal and alloy parts in air.

2.Applicable working conditions of electric furnace

2.1 The altitude shall not exceed 1000 meters.

2.2 The ambient temperature is in the range of 5-40 ℃.

2.3 The monthly average relative humidity in the use area shall not be greater than 90%.

2.4 There is no conductive dust, explosive gas and corrosive gas that can seriously damage metal and insulation around.

2.5 There is no obvious vibration and turbulence.

3. Main parameter

3.1 rated power 250KW + 10%

3.2 Rated voltage 380V, 3-phase, 50Hz

3.3 rated temperature 950 ℃

3.4 Number of control zones: 2 zones;

3.5 effective working size 3000×1600×1400mm(L,W,H);

3.6 Heating element connection method: Y;

3.7 uniformity of furnace temperature: ≤± 10 ℃

3.8 temperature control accuracy ± 2 ℃

3.9 empty furnace temperature rise ≤ 2.5h

3.10 empty furnace loss power ≤ 18%

3.11Temperature control form: thyristor, PID control

3.12. trolley moving speed ~ 5 ~ 6m / min

3.13. temperature rise of outer furnace wall ≤ 45 ℃

4.Structural features

  The electric resistance bogie hearth furnace is mainly composed of furnace shell, furnace lining, furnace door device, trolley device, electric heating elements and electrical control.

4.1 The car bottom furnace shell is welded with section steel and steel plate to form a firm frame structure.

4.2 The lining, roof and side of the furnace adopt full fiber structure and are laminated with aluminum silicate refractory fiber needle punched blanket.This structure not only reduces the height of the furnace body, reduces the furnace space, reduces energy consumption, reduces the production cost, but also prolongs the service life of the electric furnace.

4.3 The electric resistance bogie hearth furnace door device is composed of furnace door, furnace door hinge mechanism and furnace door pressing device.

  The furnace door shell is welded by section steel and steel plate into a firm frame, which is stacked with refractory fiber pressing modules.The sealing between the furnace door and the end wall of the furnace door and the front end face of the trolley adopts soft sealing to effectively prevent the overflow of hot gas in the furnace.

  Electric lifting device is adopted for the lifting of furnace door, which is mainly composed of furnace door frame, furnace door lifting beam, electric hoist, pulley, pulley shaft and other parts. The lifting and lowering of furnace door is mainly driven by the positive and negative rotation of electric hoist.The electric hoist for lifting the furnace door is also equipped with a brake device, which can effectively prevent the displacement caused by the inertia of the furnace door when it rises or falls.

4.4 The trolley shell is formed by welding section steel and built with refractory bricks inside. The easily collided parts and load-bearing parts are built with heavy refractory bricks (mixed with high-temperature binder in the mud during masonry) to enhance the structural strength of furnace lining.The traveling of the trolley adopts the traction structure, and the traveling wheel is driven by the transmission sprocket of the reducer to walk on the rail.The trolley seal adopts the soft seal between special-shaped brick and fiber cotton.

4.5 The bottom plate of the bogie hearth furnace for heat treatment adopts CrMnN heat resistant steel castings, common temperature ≤ 950 ℃. It can ensure no deformation, oxidation and cracking in use, and prevent the oxide on the workpiece from falling onto the electric heating element in the brick groove on the trolley.

4.6 The heating element of the electric furnace adopts iron chromium aluminum (0Cr25Al5) high temperature resistant resistance wires, which is wound into a sprial shapeand installed on both sides of the furnace and on the trolley. The heating element adopts spiral resistance wire heating mode.

4.7 Electrical control: The temperature control loop adotps the bidirectional thyristor power regulation trigger, and the temperature controller adopts Shanghai Guolong temperature controller to achieve the purpose of stable current and energy saving. The temperature control system adopts two zone control.The temperature rise curve of each furnace in each zone is recorded by Shanghai Dahua recorder.