Annealing Oven For Aluminum Cable Supplier
“NUTEC Bickley has just manufactured and installed an annealing oven, custom designed for processing reel-mounted compact aluminum cable. The client for this contract operates numerous plants across North, Central and South America and has a portfolio of products supplied to organizations involved in the generation, transmission, and distribution of electricity.
Arturo Arechavaleta, NUTEC Bickley’s VP, Metal Furnaces, said: “Our customer is a leading producer of electrical cable, supplying thousands of users in a very demanding market. This is a highly specialized annealing process, and NUTEC Bickley has successfully addressed key design factors such as effective air circulation, temperature uniformity, and custom loading and unloading of heavy spools.”Using a load area of 2.45m wide x 3.73m long x 2.45m high, this oven operates with a single car per cycle and can accommodate a maximum of 8,620kg (total, including the cable, spool and rack). The operating temperature is 345°C. For aluminum cable, the heat ramps up from room temperature to 345°C in a minimum of one hour. There is a variable soaking time, depending on the exact nature of each product batch to be treated.
This natural gas oven features two high-performance package burners. Each burner is equipped with a 310 stainless steel flame protector tube (to avoid flame deformation and high direct flame radiation), individual ignition, a flame failure relay, a flame detector, an ignition transformer, and a locking solenoid valve. There are two temperature control zones, designed to allow a combination of flow patterns in order to generate rapid heating and excellent temperature uniformity. Each zone has a baffle system to help direct the flow of hot air directly to the aluminum cable reels and to return this heated air back to the burners.Effective convection heating is achieved via centrifugal recirculation fans that deliver high-volume, controlled air circulation around a horizontal flow pattern, i.e. from the walls towards the center of the oven. A computational fluid dynamics (CFD) simulation was conducted to aid design of the air handling system, resulting in good uniformity. During comprehensive pre-delivery testing – carried out at the NUTEC Bickley facility – the oven’s temperature uniformity was measured at well within ±5°C.
To further maximize the thermal efficiency of this modern annealing oven, an advanced insulation system has been provided. The oven ceiling, walls and door are fully lined to a depth of 15cm with 190kg/m3 density ceramic fiber, fitted as a modular lining system. The ceramic fiber insulation offers low thermal conductivity, low heat storage and loss, thermal shock resistance, and a lightweight, easy to install construction. There is a high temperature limiter, separate from the control equipment, that protects the product from overheating.
Car movement is based on a system featuring a gear motor with chain transmission, with a guide configuration for the drag chain and car. This makes for much easier loading and unloading.
The heavy cable spool is rolled into the car, meaning single-point loading or concentrated loading on a single point is possible. The car’s construction is sturdy enough to withstand this. The oven’s vertical lift doors lower and seal automatically once the car with its spool load is in position in the oven, and the same in reverse when the cycle is complete.”
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