1. Purpose of the equipment. Technological processes used.
The vacuum electric arc melting plant “DVL-200DM” is designed for melting titanium alloys using the consumable electrode method and subsequent casting into foundry molds.

2. Features of used physical processes.
The “DVL-200DM” plant is used for melting titanium alloys. Vacuum-arc plants "DVL-200DM" make it possible to obtain such advantages as a low concentration of gases and non-metallic inclusions in the alloy, high homogeneity and density of the ingot, and significantly improve the properties of the metal.
In vacuum plants “DVL-200DM” it is possible to achieve special conditions: the highest temperatures and high pressures. Temperature control can be done either manually or using a regulator.

3. Technical description. Design features.
Brief description of units and systems for controlling and supporting the plant.
The plant consists of the following main components:
- Vacuum chamber and lids;
- Mechanism for rotating the skull crucible;
- Mechanism for moving the electrode;
- Centrifugal table;
- Vacuum system;
- Electrical equipment. Melting source "IDP-40";
- Pneumatic system;
- Water cooling system;
- Load-handling devices;
- Control system.

Vacuum chamber and covers
The chamber is a cylinder with a horizontal axis, in the lower part of which there is a vertical pipe of the container and the table of the centrifugal machine. Four camera supports are installed on the pit frame.
The following units are installed on the upper flanges of the chamber: a mechanism of moving of the electrode, a safety valve and two stroboscopic peepers. There are two vacuum system pipes and a current supply pipe for the mold heating furnace on one side of the chamber. There is an operator's platform on the other side of the chamber; there are two operator's peepholes designed to monitor the melting and pouring of the mold.
The sliding covers are pressed using pneumatic clamps of the chamber. Hoses with water, air and electrical cables are supplied to the movable lid through an energy chain. The water-cooled chamber and lids are made of stainless steel.
The chamber is also equipped with lights and peepers.

Skull crucible rotation mechanism
The crucible is used for fusing liquid metal with an electric arc from a consumable electrode. It is a graphite container shaped like a truncated cone. The crucible is inserted into a welded water-cooled body with tubular axles and current-carrying busbars. The trunnions are inserted into chamber openings that have vacuum seals. The rotation of the crucible is carried out using a gear rack and a screw transmission - a gear motor. The supply and drainage of cooling water to the crucible body is carried out through pipes. The crucible trunnions are connected to the current-carrying busbars.
The drive of the crucible rotation mechanism uses an asynchronous motor with a built-in frequency-controlled brake and a position feedback sensor.
The crucible rotation mechanism is fixed to the chamber supports. The crucible rotation mechanism may be controlled manually and automatically. While automatic filling, the crucible rotates at a specified angle, stops, makes a temporary delay and returns to its original position.
The electrode moving mechanism is connected to the upper flange of the vacuum chamber through an intermediate insulator.
The mechanism is mounted vertically on the upper branch pipe of the chamber and has a sign for the polarity of the electrode. The mechanism serves to carry out the working supply of the electrode during melting and quickly throw the electrode upward at the end of melting. The mechanism consists of a glass, a rod, a column, a transmission screw, a carriage, pneumatic cylinders, a gear motor and flexible leads: electricity, pipelines supplying cooling water and compressed air to the pneumatic cylinders.
The water-cooled glass is a welded cylindrical structure on which a column, transmission screw and gear motor are attached.
The rod with the glass enters the chamber through the upper hole, which has vacuum seals. The rod is a vertical cylindrical structure made of a steel pipe, inside of which there is a copper pipe of smaller diameter, both pipes are cooled with water. The rod is a current supply to the electrode. Flexible current leads are attached to the upper end of the rod. The lower end of the rod is located in the chamber. It has the shape of a truncated cone; a glass is installed on the cone, which is secured with half rings, nuts and bolts with a rod. The cylinder control pneumatic panel is mounted on the movable carriage. Compressed air is supplied to the panel from a pneumatic receiver. Air is supplied to the pneumatic cylinders from the panel.
Busbars (with flexible current leads attached to them) are fixed on top of the column, which serve to connect the melting source to the electrode rod.
The pneumatic cylinders are equipped with limit switches that limit the working stroke of the electrode. At the lower end of the feed screw there is a sensor that monitors the current position of the electrode.
The design of the pneumatic drive for raising the electrode ensures a shooting time does not exceed 4 seconds. The electrode supply unit is equipped with an electromechanical drive, which ensures precise supply of the electrode for melting, ensuring regulation of the arc length.
The electrode is attached by welding to the glass of the electric holder of the rod.

The centrifugal table is designed to rotate a container with casting molds. The rotation of the table is stepless, carried out by a frequency electromechanical drive, which allows you to rotate the container at a given speed in the range of up to 230 rpm.
The table is a flat disk mounted on a vertical shaft; cap bolts for fastening the container are installed on the table. The table is located in the lower vertical pipe of the vacuum chamber. The frame of the centrifugal table is a welded structure that is not rigidly connected to the chamber. The seal between the frame and the table is a flat ring made of vacuum rubber, protected from metal splashes by a special welded ring.

Vacuum system
The vacuum system of the plant provides two pumping modes: fore-vacuum and booster. The forevacuum chamber pumping mode is provided by mechanical plunger and rotary pumps, the booster mode is provided by booster, mechanical plunger and rotary pumps.
Pneumatic valves ensure the sequence of work in the technological cycle and the safe operation of the vacuum system in emergency situations.
To protect pipelines and vacuum pumps, a protective screen and traps are installed in the chamber. Exhaust traps are installed at the outlet of mechanical plunger pumps.
The pumping time to working vacuum is on average 30 minutes. Vacuum sensors are used to measure and control the vacuum in the system.

Electrical equipment. Melting source "IDP-40"
The electrical equipment includes the necessary drives for mechanical movements and operation of the vacuum system; melting source "IDP-40", control cabinets with instrumentation and control station based on the PC-PLC structure

The pneumatic system provides air supply to the actuators of the pneumatic cylinder of the vacuum valves, to the pneumatic cylinder for shooting the electrode, as well as air cleaning and preparation. The system does not require connection to the factory air line. The delivery set includes an autonomous compressor station to ensure independent operation of the plant, a receiver and an air preparation unit.
An additional receiver is installed on the overpass. The air leaving the receiver is spent on the operation of the electrode waste pneumatic cylinders.

The water cooling system is double-circuit. The first circuit is connected to the workshop cooling system. Cooling water comes from the factory water circulation cooling station through a coarse filter. The second circuit is built based on a water cooling station using collapsible heat exchangers, vertical circulation pumps and a container with coolant (treated water).
The water cooling system is equipped with pressure and drain manifolds with appropriate flow and temperature control sensors. An independent power source (gasoline generator) is provided for the crucible circuit cooling pump with automatic switching on in case of a power outage.
Load-handling devices
One is used for loading and unloading: a loaded electrode, a replaceable crucible and a glass of an electric holder. The device is a two-legged, jib crane on its own support. It consists of a column, traverse, boom and rope winch.
Another device is designed for loading and unloading the container with the mold, as well as the tray of the pouring device. It consists of a rotating frame, a transverse trolley, a longitudinal trolley, a load lifting winch, a longitudinal chain mechanism and a frame rotation drive. The device is suspended by means of a transverse trolley from an I-beam, on which the sliding cover trolley is also installed. A frame capable of occupying a working horizontal or vertical position is attached to the transverse trolley on hinges. A longitudinal trolley with cargo blocks moves along the frame. A cargo winch is installed on the frame, which lifts the container using a movable block with a fourfold reeving.

The control system of the plant is built according to the PC-PLC structure and includes an industrial computer (upper level), a programmable logic controller (lower level).
The controller performs the functions of technological process control, a computer, and a terminal control task (visualization of the state of the unit elements, storage of process history files, events and errors).
The plant control system performs the following functions:
- transition from automated control to manual;
- control of the operation of the vacuum system in automated, manual and adjustment modes;
- control of the speed of movement of the electrode;
- control of the rotation speed of the centrifugal table;
- the ability to record the parameters of the melting process and archive the results;
- observation of the melting area using a video camera.
The control system in real time documents the main technological parameters of the arc melting process (archival task). The operator determines the frequency of polling and recording into memory. Data is stored in EXCEL format.