Deep steaming is a special surface steaming process that takes place under the sheet. You will need an additional vacuum device for deep steaming. This device can be either mobile or rigidly installed in the greenhouse floor.

I) Mobile vacuum system (at 50cm steaming depth)

For this purpose, you have to lay pipes for air suction and install a special fan above the ground. It does not require much work or expense. At the pipe ends, heat-resistant hoses are burrowed into the soil at the desired depth. Through this steaming method, a uniform negative pressure is generated in the soil and the steam is sucked into the depths.

II) Rigidly-laid drainage pipes (up to 80 cm steaming depth)
In this method, drainage pipes are rigidly laid under the ground and connected to an extra exhaust station. There are professional firms who specialise in installing such systems.

Attention must be paid to the fact that, in this case, deep steaming will cause a strong increase in energy consumption. Depending on the steaming depth and the soil properties, this steaming method will very likely require more than 3 litres of heating oil per square metre.

In the case of a mobile exhaust system, a central suction line consisting of galvanised quick-coupling pipes is connected to the special fan by 1.5m spacing. The hose ends are inserted to the desired steaming depth with a special inserting stick.

Suction pipes can be laid easily and quickly. The same applies to their connection to the exhaust turbine.

Like with the sheet steaming system, the surface to be steamed is placed under a special steaming sheet, weighted on all sides and sealed. The steam is then pumped under the sheet with the injector via a protective tunnel. For short surfaces (less than 30m), the steam is filled in from the front side. For longer surfaces, the steam is introduced in the middle of the bed, with a T-distributor at both sides.

As soon as the steaming sheet is inflated by the steam pressure and tension of about 1m in height is achieved, the exhaust turbine has to be turned on by a push-button switch.

At first, the air in the soil is extracted via the suction hoses inserted into the soil. This creates a vacuum, which forces the steam cushion under the sheet downwards.

In the initial stage, the pressure is quickly sucked under the sheet so that the exhaust turbine switches off earlier.

With increasing saturation, the fan runs for longer, or the switch intervals become shorter and shorter.

At the final stage, when the desired steaming depth is achieved, the fan runs non-stop and blows out more and more steam at higher temperatures. To prevent the steam escaping, it is led back under the sheet.

Like in all other steaming systems, about 20-30 min of re-steaming is required. Depending on the steaming depth, you will need 7-8kg or more steam per square metre of surface.

In all surface steaming methods, the soil must be loosened first. The depth effect depends on the soil being adequately loosened. This simple and low-price system is suitable for boiler systems with steam output from 350kg.

The surface performance per working cycle depends on the steam boiler size.The surface performance per working cycle depends on the steam boiler size.

Depending on the soil properties and ambient temperature, the steaming time is 1-1.5 hours at 10cm steaming depth and about 80°C soil temperature.You can reduce the steaming time by covering the steaming sheet with a special insulation mat.

For a deep steaming effect, you always need an exhaust system.