High- & low pressure steam boiler

Steam for soil steaming is mostly produced in high or low pressure steam boilers.
All steam boilers, which produce steam pressure of more than 0.5 respectively 1 at (gauge)  are high pressure steam boilers. They have to meet several special security regulations for operation. In contrast low pressure steam boilers are less complicated to operate.

In general, strict rules and regulations are in place for the usage of steam boilers in the Federal Republic of Germany.

Professional producers in the horticulture, agriculture and compost industry should get detailed information what rules apply to the operation of steam boilers prior to purchase. Many steam boiler manufacturers, in particular European ones in France and Italy, don’t meet all German regulations. For example, in Germany, steam boilers have to be fully insulated in order to minimize injuries and to comply to federal emission protection laws which require waste gas loss to max.9 % at a certain output. Therefore steam boilers have to reach 90% efficiency.

Schematische Zeichnung eines modernen Niederdruckdampfkessels mit Dampf Überhitzer und Rauchrohrsystem der Fa. MSD GmbH (Möschle Seifert Dämpftechnik, Durbach)

Schematical drawing of a modern low pressure steam boiler with steam superheater and smoke pipe system from MSD (Möschle Seifert Steaming Technology, Durbach, Germany)

In professional horti- and agriculture mostly low pressure steam boilers are used. Modern models of this machine have a horizontal flame tube, in which a flame is generated through horizontal fuel injection. The flame tube is completely surrounded by the water and the vaporization chamber above. This design is very robust against load fluctuations: it’s easy to clean the inside and the fume hood as well as simple to operate. In order to increase efficiency, flame tube steam boilers possess fume pipes which guide burnt gas after passing the turning chamber through the water chamber for energy release, before they are emitted through the chimney. Besides flame tube / fume tube steam boilers there are further designs such as water pipe steam boilers or cylinder steam boilers which are less suitable for steam generation in the agricultural sector. Water pipe steam boilers are only suitable for smaller companies where relatively low amounts of steam are required. In particular high pressure steam boilers have higher purchasing prices and higher operating costs.

Despite longer heating times due to bigger amounts of water in the water chamber low pressure steam boilers prevails in the horticulture, agriculture and compost / turf sector due to their high usability and ruggedness.