Vacuum pressure impregnation equipment

Use

(VPIE) is utilised for impregnating wood with water solutes based on chromium, boron and copper. Most commonly used are cylindrical vessels of various diameters and lengths. This however always depends on the specifi customer requirements. Special materials are used for its production always in accordance with the required working pressure.

Closing the autoclave

Its bottom part (i.e. the lid) is one of the most important components of the autoclave. Therefore its safe closure is extremely important. It is implemented by means of rings and using a hydraulic system. Rubber seals with varying cross-sections are used for sealing their bottoms.

Rails and trolleys

The autoclaves are always equipped with interior rails. When they are fi lled with an impregnation solution it is their design that ensures the prevention of the trolleys from fl oating. The trolleys are constructed of steel profi les, thereby guaranteeing their rigidity, their strength and their endurance. The trolleys’ mobility is ensured by the ball bearings with which the wheels are equipped. Based on the customer requirements it is also possible to provide external rails. These can be of a simple design or can be driven.

The storage tanks

Most frequently it is the rectangular steel tanks that are used for storing the impregnating solution. Their volume is always 30% greater than that of an empty autoclave. This enables autoclaves to function with a minimum content of wood and it also not necessary to fi ll-up the impregnating solution so frequently.

Most often the storage tanks are placed beneath the autoclave. This has the advantage that the draining of the autoclave is achieved by means of gravity. This design also reduces the number of valves and the amount of piping that is required for the operation of the autoclave. The one disadvantage is the necessity of it standing on a concrete foundation. In the second variant the tanks are placed directly on the concrete. For example they may stand either beside or behind the boiler. In this case it is necessary to use transporter pumps and additional valves for emptying the autoclave.

A functional description

Monitoring:

For monitoring the impregnation process the autoclave is equipped with monitoring devices:

a visual, digital pressure gauge
electromagnetic flowmeter

The pressure pump:

This is used for creating pressure inside the autoclave and for this centrifugal pumps of up to 16 bar are utilised.

The safety valve:

For safety reasons each autoclave is provided with a spring-loaded safety valve.

The vacuum pump:

To create a vacuum (-0.85 bar) inside the autoclave water ring pumps with diff erent outputs are used, depending on the capacity of the boiler.

The valves and the piping:

To ensure their safe operation only the most essential valves and piping are utilised for the autoclaves. The valves are either controlled electrically or pneumatically.

The float switch:

This serves to arrest the vacuum pump when the autoclave is fi lled with the impregnation solution.

The control system:

The autoclaves are available with either manual or automatic control. Most of the equipment is supplied with a fully automated PLC controlled system. Thanks to the touch screen, it is possible to set the impregnation parameters. The system also enables the recording of data (e.g. pressure and fl ow rate) during the impregnation, which can subsequently be displayed in a log (in Excel) or in print. All of this activity is located in the electrical cabinet together with other necessar elements (relays, contactors, etc.)

Additional examples of autoclaves

An autoclave designated for the vulcanisation of rubber in Russia. Inside the autoclave there are electrical heating elements and also interior rails.

Parameters:

Ø 1,8 × 8 m
operating temperature: 180 °C
work pressure: 8 bar

An autoclave for steaming located in the Slovak Republic. The sheath of the autoclave, its underside and its closing mechanism are all made of stainless steel.

Parameters:

Ø 2,3 × 15 m
operating temperature: 130 °C
work pressure: 6 bar

An autoclave designated for the forestry university.

Parameters:

Ø 0,5 × 2 m
work pressure: 8 bar

ABOUT US

Since 2000, Fadoktor Mérnöki Iroda Kft. and its legal predecessor have been a family business dealing with wood protection, manufacture, distribution and trade of sawmill and further processing industrial products, and especially with the design and construction of playgrounds.