The UVN-1500M furnace is designed for vacuum annealing and dehydration of large-sized welded units and assemblies made of titanium alloys.

Results of vacuum annealing of titanium alloy products:
- the geometry of the annealed product is preserved;
- a protective film is formed that prevents hydrogenation during the operation of the structure;
- cyclic strength is preserved;
- unwanted residual stresses in the structure are removed after assembly;
- the tendency of the metal to hydrogen embrittlement is eliminated;
- the hydrogen content is reduced to the required value.

The UVN-1500M furnace consists of the following units:
1. Chamber.
2. Heating section.
3. Vacuum system.
4. Pneumatic system.
5. Support.
6. Cap.
7. Guide.
8. Frame.
9. Water conduit.
10. Power cabinet.
11. Control cabinet.
12. Electrical wiring.
13. Water cooling system.
14. Rollback device.
15. Loading device.
16. Shutter.
17. Left screen.
18. Fan.
19. Cover.

The structure, operating principle of the unit and its components.
The operating principle of the UVN-1500M unit consists of heating the workpiece in a vacuum to a certain temperature, maintaining it at this temperature and cooling it in a vacuum and inert gas environment.

Structurally, the UVN-1500M furnace is designed as a vacuum chamber mounted on supports. On one side, the chamber is closed by a lid, on the other side by the bottom of the loading device.
The bottom of the loading device is equipped with: a fan, brackets for fastening the device with the workpiece. The bottom of the loading device is pressed against the flange of the chamber by a shutter.
On the same side of the chamber, along its longitudinal axis at the level of the workshop floor, there is a rollback device that allows the loading device to be moved away from the chamber for loading and unloading workpieces.
Under the chamber between the supports, there is a water cooling system.

The vacuum system is located on one longitudinal side of the chamber and the end closed by a lid.
Along the other longitudinal side of the chamber there are: a power cabinet, a control cabinet, transformers for heating purposes, and on the chamber itself on this side there are elements of the electrical wiring system.

Inside the chamber there are heating sections with guides, frames and guides. The guides and frames are designed to accommodate the loading device with workpieces on them.
The cylindrical chamber is made of sheet stainless steel. Flanges are welded to the ends of the cylinder for fastening the cover on one side and the shutter and loading device on the other.
The chamber has a water jacket divided into five zones.
Flanges are welded into the chamber for fastening the thermocouples of the vacuum sensors, current leads, and vacuum system pipelines. The chamber is equipped with two stands for installing it on supports.

The loading device is designed to load and unload products from the chamber. The loading device consists of units:
- Trolley,
- Bottom,
- Right screen.
The trolley is a welded structure that has wheels and an electric drive for moving it along the guides of the rollback device. The trolley has plates for fastening the fan electric motor, bottom brackets, and a protective casing covering the fan electric motor.
The bottom has a welded structure with a water cooling jacket. The bottom has a flange for fastening the fan and protrusions along the outer diameter for engagement with the shutter brackets. There are four spring dampers in the bottom, to which the first screen is attached. The dampers are designed to compensate for the temperature expansion of the heating sections during the technological process. There is a groove in the bottom, in which there is a rubber gasket, allowing for sealing the connection of the chamber with the bottom.
The right screen has a welded body made of heat-resistant stainless steel with an opening for placing the fan impeller. The welded body has screen thermal insulation made of thin-sheet heat-resistant stainless steel.

The shutter is designed to seal the connection of the chamber with the bottom of the loading device. The bottom is pressed against the flange of the chamber using wedges fixed to the brackets and the bottom. The rotation of the brackets, fastened with a ring, is performed by a screw-nut transmission. The screw is driven by an electric motor through a gearbox. The angle of rotation of the wedges is adjusted by moving two limit switches.

The fan is used to cool the product with the loading device in the chamber, in an inert gas environment (argon). The fan moves the gas from the heating zone to the gap between the walls of the heating sections and the water-cooled walls of the chamber. The fan consists of an impeller, a welded casing, inside which a shaft is installed, driven into rotation by a V-belt transmission directly from the electric motor.

The heating section consists of a welded cylindrical frame with pins welded in the radial direction. Screen thermal insulation made of thin-sheet stainless heat-resistant steel is attached to the pins and heaters on ceramic insulators.
Each section contains heaters and racks for attaching guides.
Each heating section rests on the wall of the chamber through rollers that ensure the movement of the sections during thermal expansion.
The left screen consists of a welded frame made of stainless steel. The screen is welded to the fifth heating section at the manufacturer's plant.

The retractable device consists of support frames with guides, an energy chain and trays along which the energy chain moves.

The water cooling system is designed to supply and drain water to the units of the plant that require cooling during operation. The system is divided into two circuits: a cooling circuit for the vacuum system and a cooling circuit for the remaining units of the plant. The system must be connected to the workshop water supply system. Water flow through the channels is controlled by water control units complete with sensors that monitor the water flow and its temperature.

The pneumatic system is used to control the pneumatic drives of the vacuum valves. The system includes an air preparation unit, pneumatic distributors and pipelines.

The vacuum system is used to create a vacuum in the chamber and to release inert gas into it when cooling the product. The system consists of a pumping line to create a medium vacuum and two lines for a high vacuum.

The UVN-1500M furnace can operate in manual and automatic control modes. The control system is based on computer technology and allows recording the main parameters of the technological process and exercising full control over its execution.

Vacuum unit UVN-1500M for annealing welded structures made of titanium alloys

Currently, instead of the UVN-1500M furnace, modern furnaces of the PV-900 type are produced in various modifications.