Download article in PDF format => New laboratory vacuum chamber electric furnace of resistance SNVE-2.4.2_16-OTTOM
Vacuum electric resistive furnaces have significant advantages. They provide: possibility of non-oxidative heating of metal up to high temperatures and saving the original surface, reduction of heat losses compared to the furnaces with protective atmospheres, maximal fire and explosion safety of technological processes, etc. [1, 2]. This circumstance predetermined a wide range of heat treatment processes that are carried out using them. Such processes include tempering, annealing, heating for the hardening metal products; sintering in powder metallurgy; soldering of especially important parts and structures; refining refractory metals from gases; degreasing metal surfaces, drying various materials, etc. The most important peculiarity is that these furnaces solve the problem of using refractory metals as heaters, and, therefore, these furnaces have no competitors when heated in the temperature range above 1000o C. Therefore, vacuum electric resistive furnaces have become the most universal type of electrothermal equipment and the most widely used [3].
Until recently, there was no serial production of vacuum electric furnaces in Ukraine. Since 2003, this niche has been occupied by the company “Trade House “OTTOM”, Ltd.
Up to date, our company has developed and manufactured for the industry a whole series of vacuum electric resistive furnaces. Another novelty has become development of vacuum batch electric resistive furnace (model SNVE-2.4.2/16-OTTOM)
The purpose of this publication is to familiarize potential consumers with a vacuum batch electric resistive furnace (SNVE-2.4.2/16-OTTOM) (see fig). This type of electric furnace is a qualitatively new relative to the latest version of the SNVE-2.4.2/16-I1, which has been developed in the 70s of the last century.
GENERAL INFORMATION
New generation batch vacuum electric resistive furnace SNVE-2.4.2/16-OTTOM is purposed for various thermal processes (annealing, sintering, synthesis of compounds, degassing, and other processes) in vacuum at temperatures up to 1600 ° C. Insignificant gas emission of charge material, materials of heaters, screen insulation and other structural elements is provided. It is possible to work in an environment of high purity neutral gases with an above atmospheric pressure of no more than 0.02 MPa (0.2 kgf / cm2). This case, the working temperature is determined depending on the physical parameters of the gases.
The electric furnace is environmentally friendly. There is no release of chemically active gases into the atmosphere of the workshop, which ensures its explosion and fire safety during operation. The electric furnace can be used both as a laboratory for scientific purposes, and as a common industrial for the aviation, electronic, radio, electrical, engineering and other industrial branches.
The operation of the electric furnace, including thermal processes and the control of the vacuum system, are realized according to a program using an automatic control system, made on the basis of microprocessor devices. The electric furnace is produced fully automated in terms of heating and vacuum control systems according to the program.
Alphanumeric digital electric furnace
C – type of heating – resistive;
H – the main structural feature – batch;
B – the nature of the medium in the working space – vacuum;
E – type of thermoinsulation – all metal;
2 – width of the working space, dm; (200 mm)
4 – length of the working space, dm; (400 mm)
2 – height of the working space, dm; (200 mm)
16 – nominal temperature, hundreds of ° C.
DESCRIPTION OF DESIGN
The electric furnace СНВЭ-2.4.2/16-OTTOM consists of the following parts:
- vacuum chamber;
- heating module;
- vacuum system
- water cooling system;
- furnace transformer and power supply;
- control module;
- temperature control system;
- safety system.
All elements of the electric furnace are mounted on the common frame in the form of a single assembly and transport hub.
The vacuum chamber is a cylindrical, horizontally oriented body, closed on both sides with doors attached to the body with hinges and bolts. The cover and body designs are equipped with water-cooled jackets. The vacuum system consists of the oil diffusion pump, two mechanical forevacuum pumps, vacuum gates and the required number of valves and vents.
The water cooling system consists of a collector, a drain funnel, cooling jackets, electric furnace design elements and diffusion oil pump connected with a rubber-fabric hose attached to the fittings of the water-cooling system elements. Cooling water flow includes visible jet break.
The heater is power supplied from a furnace transformer mounted on an electric furnace frame. The current measuring transformer included in the heater current control system is installed on the cable connecting the low voltage coil of the transformer with the regulating device.
Regulation of the thermal mode is obtained via changing the power supplied to the heater using a thyristor voltage regulator included in the primary coil of the furnace transformer. The control signal of the thyristor voltage regulator is formed and supplied from the regulating microprocessor device. The elements of the vacuum system are controlled using a programmable controller. Instrumentation and apparatus are located in the control cabinet.
The design of the electric furnace meets the safety requirements of GOST 12.2.007.9-88. Safety conditions of work must be provided by the enterprise-consumer in accordance with the “Rules of safety in the operation of electrical installations by the consumer” and operation documentation. The degree of protection of the electric furnace is IP10 GOST 14254-96, the control cabinet is IP40.
SPECIFICATIONS
- Installed power, 35 kW
- Rated power, 29 kW
- Idling power 27 kW
- Nominal temperature within the working space, 1600 ° С
- Temperature uniformity within the working space, ± 10 ° С
- Stability of temperature maintenance, ± 5 ° С
- Dimensions of working space, mm:
– width 200
– length 400
– height 200
- Mass of the charge, 30 kg
- Environment within the working space – vacuum
- Ultimate residual pressure in the cold state within the electric furnace, 6.65 × 10-3 Pa (5 × 10-5 mm Hg)
- Rated voltage, V 380/220
- Rated current frequency, 50 Hz
- The number of the heater phases 1
- Water consumption for cooling, 1.5 m 3 / h
- Overall dimensions of the electric furnace, mm:
– width 2000
– length 2500
– height 1850
- Electric furnace weight, 1.5 t
The warranty period is 1 year from the date of commissioning of the electric furnace to operation, provided the rules of operation, storage, transportation and installation.
OPERATING CONDITIONS
Ambient temperature – from 5 ° C to 35 ° C, relative humidity of the ambient air – not higher than 80% at 20 ° C and not more than 50% at 35 ° C in an explosion-proof environment that does not contain aggressive gases and vapors in concentrations which are hazardous for the equipment components, materials and electrical insulation, unsaturated with water vapor and conductive dust; when the fluctuations of supplied voltage do not exceed 5% of the nominal.
The electric furnace is installed directly on the floor without foundation. The design meets the requirements of ergonomics. The electric furnace meets the safety requirements of GOST 12.2.007.9-93. Protection against electric shock of the electric furnace corresponds to class 01 according to GOST 12.2.007.0-75. The degree of protection via the shells IP20 corresponds to GOST 14254-96 (IEC-529-89).
COMPLETENESS OF DELIVERY
Package Includes:
- electric furnace partially disassembled;
- power and control module;
- a set of spare parts according to the list of spare parts;
- a set of operation documentation according to the list of ED.
ЛИТЕРАТУРА
1. В.М. Шулаев. Термическая обработка с применением вакуума. Оборудование и технологии термической обработки металлов и сплавов. Харьков, 2002, ч. 1, с. 30-32.
2. Вакуумная техника. Справочник / Под общ. Ред. Е.С. Фролова, В.Е. Минайчева. М.: «Машиностроение», 1992.
3. В.М. Шулаев. Вакуумные технологии термической обработки сталей и сплавов в машиностроении. // БИЗНЕС-МОСТ. 2007, № 1-2, с. 20-21.