This invention relates to a drier, which is intended for drying stone structures at renovation objects. In this domain, various types of plate driers and infrared resistors are used for heating/drying a structure. The devices are left at the object for several weeks, with measurements made at intervals. Some companies sell accelerating micro- wave drying, however, due to hazardous radiation, this drying technique is inapt for use on a large scale. Air-circulated plate driers available on the market are not based on the same technology. The present invention is based on the idea of pressure blowing heating air and pressure blowing cooling air at room temperature into the structure.

Plate driers are inapt to heat/dry the entire thickness of thoroughly wetted concrete. Infrared resistors achieve reasonable good heating of the structure, yet the energy loss is great and heat alone does not dry a concrete structure. Due to radiation, ac- celerated heating of an intermediate floor cannot be performed from the top floor with the inhabitants being present on the bottom floor. What is more, also the operator of the device is exposed to radiation.

In this invention, hot air and room temperature cooling air is pressure-blown in alignment into the structure to be dried. The cooling will proceed evenly in the structure, so that the structure will not be damaged by temperature variation.

The drier of the invention is characterised by consisting of a housing, in which overpressure can be generated by means of a blower, with the air discharged from the housing directed to the plane to be dried below, such as a concrete floor, and that the housing comprises one or more thermal resistors, by means of which the drying air can be heated.

Different embodiments of the invention are described in the dependent claims of the set of claims.

When the resistors are in on-position, the entire thickness of the structure will be rapidly heated, because the pressure-blown hot air penetrates into the pores of the structure. When the resistors are in off-position, the structure will cool evenly and release moisture when exposed to the pressure-blowing. Separate devices are used for the machine blowing and the moisture removal from the room. The invention is applied in continuous repair operations at several objects up to the final measurements and the rebuilding work. The drying periods will be several weeks shorter and the required energy consumption can be more effectively utilised in aligned operation. The invention is explained in greater detail below with reference to the accompanying drawing, in which

Figure 1 illustrates the drier viewed from below without a perforated steel plate, Figure 2 illustrate the drier viewed laterally in cross-section and Figure illustrates the detached perforated steel plate. The drier, which is intended for drying stone structures at renovation objects, consists of a housing 1 , in which overpressure can be generated by means of a blower 11, with the air discharged from the housing directed to the plane to be dried located below, such as a concrete floor 10. The housing comprises two thermal resistors 5, by means of which the drying air can be heated. The thermal resistors may have a power of 2-4 kW each. Protective plates 7 are provided above the resistors 5. The blower 11 is connected via a pipe 4 to a set of pipes 3 with apertures at regular intervals, which is located within the housing 1. A perforated steel plate 9 is provided under the drier, the fastener 6 of the resistors 5 and the set of pipes 3 being fixed to the perforated steel plate. The housing 1 consists of a polyurethane plate, which is lined with an aluminium plate 2. A heat regulation unit and a thermostat 2 are provided above the drier.

The light-weight polyurethane frames reinforced with the aluminium plate 2 and the perforated steel plate 9 allow the production of driers having different designs and dimensions.