Thu, 14 Jun 2018 02:30:55 +0000

Vacuum suspended melting furnace supply

1, the furnace

The furnace body consists of three parts: melting chamber, feeding, measuring and operating platform.

The operating platform is in the front of the smelting chamber for operating the mechanism on the upper part of the furnace body and using the observation window on the furnace body.

The melting chamber is cylindrical, with an inner diameter of 1.5 meters and a total axial height of 1.7 meters. The chamber wall of the melting chamber has a double-layer water-cooled jacket structure, both layers are made of stainless steel, the outer wall is treated with sandblasting and sublight treatment, and the inner wall is polished.

In the front room left with melting electrode electrode interface, interface is on the right with a crucible cooling water tube, in the upper chamber before setting up a bunker and two observation window, one of the observation window to install infrared thermometer.

The front room is provided with an observation window interface in the front, which is equipped with smoke shielding baffle under all observation Windows, and the baffle is turned away when necessary. A feeder interface is also provided above the front chamber.

In the back room of the left have high vacuum valve of the vacuum interface tube, the right for mould cooling water supply of water, electricity and heating current interface, in the Chambers of the below are installed centrifugal casting casting interface.

The melting chamber is also equipped with a tamping rod interface, a temperature measuring rod interface, a pressure gauge interface, a vacuum gauge pipe interface, and an anti-explosion pressure relief device interface.


Vacuum suspended melting furnace supply


2. Inductive power

intermediate frequency induction power supply is used in suspension smelting, 950kw, frequency 9-11khz.

The current generated by the power supply is lowered through the output transformer, and is connected to the coaxial water-cooled electrode in the electrode rotation axis through the water-cooled cable and the wiring turntable, and then to the sensor around the cold crucible.

3. Smelting and casting system

The system consists of cold crucible, water rotating shaft of crucible, coaxial water cooling electrode, induction coil, crucible frame, mould and so on.

Three water-cooled copper crucible, respectively smelting Ti;

The crucible is made of forged anoxic copper, divided into several valves, each with a cooling line.

The crucible and the induction coil are fixed by the crucible frame, the left side is combined with the coaxial water-cooled electrode installed in the front chamber, and the right side is combined with the crucible rotating shaft installed in the front chamber. Connect the rotating shaft of the crucible with stainless steel hose to supply cooling water to the crucible.

The coaxial water-cooled electrode is equipped with a rocker outside the furnace body, which can control the rotation of the electrode in the electrode cylinder and drive the induction coil, the crucible and the water rotation axis of the crucible synchronously through the crucible frame.

At the bottom of the chamber body is equipped with a centrifuge, mold to the centrifuge tray (Φ within 800 mm). The speed adjustment of centrifuge is regulated by vector frequency conversion governor and equipped with brake resistance, which can stop at any time.


4. Process operation system

The following operating mechanisms are designed inside and outside the furnace body:

1. Electrode rotation axis: coaxial water-cooled electrode rods are installed in the rotating shaft. They are combined with water-cooled cables on the outside and induction rings in the furnace to deliver current to the induction coil. The rotating shaft can be rotated manually, which drives the tilting of the crucible frame and is used for the casting of the tilting crucible.

2. Feeder: it is installed on the feeder interface of the front chamber for filling the crucible during smelting and manual operation.

3. Tamping mechanism: it is used to handle the bridge burden without opening the furnace so that it falls into the molten pool and is operated manually;

4. Heat shield plate: for shielding the heat radiation from the molten pool in the crucible to the upper part of the furnace body;

5. The bottom protection plate is laid on the bottom of the furnace to protect the bottom of the furnace from the scald of spilled liquid metal;

6. Inner lamp: lighting device is set in the furnace to observe the state of the furnace after closing the cover.


5. Vacuum and argon system

The vacuum system adopts two type 2X-70 rotary vane pumps, one type zjp-600 roots pump, one type KT-500 diffusion pump, DN500 cold trap, DN500 pneumatic vacuum baffle valve, and all types of front – stage valves and stainless steel vacuum pipes.

After the abnormal pressure in the furnace is detected, the maximum pumping speed of the 2X-70 rotary vane pump and zjp-600 roots pump can be automatically started to extract the abnormal pressure gas in the furnace. The system simultaneously cuts off the main power supply of smelting and sends out sound and light alarm signal.

The argon gas system comprises an argon-filled valve, an overpressure relief valve, an air release valve, a stainless steel argon gas pipeline and an argon gas source. The argon source is provided by the user and equipped with high purity argon purifier.

The vacuum valves of the system are all pneumatic valves, while the valves of the argon system are electromagnetic valves, and their control includes two modes: simulated screen manual operation and program control. In program-controlled mode, the argon charging process can be completed within 20 seconds of closing the high vacuum valve and the designed pressure value can be achieved.


6. Water cooling system

Cooling system – USES a closed cooling water circulation system, which supplies water to crucible, induction coil, power supply, furnace body and other parts.

Main pump flow 80M3/h

Motor power 15Kw

Spray pump power 2.2kwx2

1.1 KwX3 fan

Cooling capacity 380000Kcal/h

Each cooling branch in this part shall be equipped with a pressure gauge, flow meter and thermometer, with signal output for alarm and protection. Tap water should also be connected to the distributor through the solenoid valve, when a sudden power failure or pump stop using tap water cooling.

7. Control and safety protection system

The control system adopts the mode of PLC+ analog screen, and some functions are controlled by program.

The system has the following functions:

1) operation process control: refer to starting and closing of water pump, slide valve pump, roots pump, diffusion pump, vacuum pneumatic valve, argon-filled valve, centrifugal casting, pressure relief valve of furnace body and inner lamp.

2) parameter measurement: the measuring instruments include: digital composite vacuum meter, melting heat couple thermometer, infrared thermometer, waterway temperature controller, electric contact pressure gauge;

Using these instruments, the vacuum degree, melting temperature, water temperature, water pressure and gas pressure in the furnace during the operation of the equipment

You can see it.

3) program control: the program control program of this device has the following items:

Interlocking the operating sequence of each system and each component — automatically forbid the action when wrong operation occurs, such as setting the running order of water pump and induction power;

Program control of vacuum system operation — control of operating conditions and sequence of each vacuum pump and vacuum valve;

Process control of argon filling, etc.

4) alarm protection: the alarm protection items set up include:

The protection of the crucible (2 channels), the induction coil, the water temperature of the water tank is too mild and the water pressure is too low — first alarm, then cut off the induction power;

Pressure over-limit protection of furnace body — there are two sets of pressure relief valves on furnace body. There is also a manual pressure relief valve with slightly higher pressure set;

Protection of crucible from power failure or water pump shutdown in workshop – automatic water supply

Note: the induction power supply has separate control system and alarm protection system.