METHOD AND APPARATUS FOR DRYING A FLOOR STRUCTURE DAMAGED BY MOISTURE OR WATER

Abstract: A method and apparatus for drying out a concrete flooring structure (1) with associated filling (4) and floor (5). Drying air is taken through many narrow holes in the floor. Outlet openings are arranged. Injection tubes (10), which are connectable to a compressed air source, are inserted into the holes. A compressed air stream with low absolute humidity and substantial excess temperature, with reference to the initial temperature of the flooring structure, is supplied to an air-permeable layer, e.g. the filling (4) via the injection tubes (10). A heater (14) heats the floor surface to the same or higher excess temperature. After a given lowering of the relative air humidity in the air-permeable layer, the temperature of the compressed air is lowered and the floor heating reduced and the cooler compressed air stream is maintained until a given drying-out of the concrete is also achieved. The heating and cooling cycle is repeated as necessary until the desired final result is obtained. The compressed air source is equipped with a drying apparatus, cooling battery and heating battery for the air.

Description: Method and apparatus for drying a floor structure damaged by moisture or water DESCRIPTION Technical Field The invention relates to a method and apparatus for drying out a concrete floor structure with its associated filling and flooring that have been damaged by moisture or water. Drying takes place with the aid of air which is led into air-permeable layers in this structure. Background Art It is already known to take hot air, with the aid of building dryers or similar apparatus, under the floor through one or more broken-up and rather large openings in the floor, to allow the hot air to take up moisture before the former departs through other openings, which it has also been usually necessary to provide by breaking up the floor locally. The large operations on the floor are a consequence of large air streams being necessary to provide any noticeable result. The method has been found to have no effect in the cases where the concrete slab has been well soaked with water, which could often have been the case with floors at, or below, the ground level. Such damage has not been able to be rectified in general without breaking up and removing the entire floor. Disclosure of Invention The object of the invention is to provide a method and apparatus which makes it possible, in most cases, and without even locally breaking up the floor, even to dry a concrete support structure which is complete¬ ly soaked with water. The intended result is obtained by the method and apparatus being given the characterizing features disclosed in both of the independent claims in the follow¬ ing array of claims . Brief Description of Drawings The method and one embodiment of the apparatus is described in detail in the following with reference to the accompanying drawings. Figure 1 schematically illustrates a vertical, partial section through a support structure with filling and flooring, apparatus in accordance with the invention being applied in and on the floor. Figure 2 schematically illustrates in plan the principle of localizing a plurality of narrow holes in the floor for the supply of drying air. Figure 3 is a block diagram of the most important components included in an apparatus in accordance with the invention. Figure 4 illustrates to a larger scale an injection tube for air. Preferred Embodiments The floor illustrated in Figure 1 is an example of a type of floor structure which has seldom allowed itself to be rehabilitated after moisture and water damage without breaking up the whole floor. The support structure 1 itself consists of a concrete slab resting on an insulating layer 2, e.g. of hot-cut and thereby substantially waterproof and diffusion-proof cellular plastics, which in turn rests on a draining layer 3 in the ground. Above the concrete slab 1 there is a screeded sand layer 4. On this rests in turn the flooring 5, e.g. formed from chip boarding or parquet flooring boards. A diffusion-tight film 6 may be arranged between the filling consisting of the sand layer 4 and the flooring 5. The spaces between the grains of sand of the filling as well as the space between the film 6 and flooring 5 form air- permeable layers in a horizontal direction. If there is water damage, a floor of this kind can take up consider¬ able quantities of water. The concrete slab 1 can be completely soaked with water, and it may also be that there is water above, as well as below, the slab. To enable drying out, a plurality of narrow holes 7 are drilled through the flooring 5 down to the filling 4. These holes are intended for use as supply orifices for drying air to the filling. Outlet openings for exhaust air from this air-permeable layer are arranged by removing the skirting boards, air gaps 8 generally being thus obtained along the walls 9 adjacent the floor in the room without f rther measures. In substantially every one of the holes 7 there is inserted an air injection tube 10 with sufficient length for projecting into, and almost through, the sand layer 4. The holes 7 are distributed over central portions of the floor surface and arranged in several parallel rows. They are suitably arranged with a spacing of 10 - 50 cms in each row, preferably about 15 cm. The diameter of the holes do not >need to exceed 2 nuns , since the tubes 10 are suitably made from piping with this diameter as a maximum. Figure 4 illustrates more closely how such a tube has its upper open end inserted in the wall of a hose 11. The wall of the tube is in turn provided with some axially spaced holes 12 serving as outlet orifices for drying air at different levels in the filling 4. The length of the tubes 10 and the number of holes 12 is adjusted to the object being worked on. The bottom ends of the tubes do not need to be open. A hose 11 is disposed along each row of holes 7 in the floor. Such a hose is illustrated in Figure 1 , but the hoses have been excluded from Figure 2. As is illustrated in the principle sketch, Figure 3, the hoses are adapted for being connected to a pressurized air source 13 delivering compressed air, which has been dehumidified, and also treated with respect to its temperature. A heater, in the form of one ' or more mattress¬ like heating pads, is placed on the floor (Figure 1), the pads being upwardly covered with a heat-insulating and preferably reflecting material 15, which may either be integral with the pads or made as separate matting. The heating pads are heated by unillustrated internal hot water coils or electric coils. The drying process proper is started after these preparatory measures by the compressed air flow, which has a low absolute humidity of preferably about 0.2 gram 3 water/m air and substantial excess temperature in relation to the initial temperature of the floor structure, being supplied from the source 13 to the sand filling 4 via the hoses 11 and injection tubes 10. A suitable temperature is normally 30 to 50 C. The floor surface is simultaneously heated by the heater 14 to the same temperature as the compressed air, or to a higher temperature, preferably about 10 C higher. This supply of dry and hot compressed air as well as the floor surface heating is maintained substantially unaltered until the moisture in the air in the filling in the vicinity of some outlet gap 8 has sunk to a predetermined first value. A revelant measuring point 16 can often be obtained by removing a threshold (Figure 2) and finding a point in contact with the air- permeable layer, i.e. the sand filling 4. The pre- determined first value is suitably a relative humidity of 60 - 65 %. It may also be suitable to drill a hole under the threshold down into, or through, the concrete slab 1 for measuring the temperature under it, or in it, near the underside of the slab in the latter case. The measuring point can be of value partly for determining the original temperature level of the floor structure and the temperature gradient, and also for monitoring temperature changes at the underside of the concrete slab. It is suitable here not only to ensure that the mentioned first value for the moisture in the air which has passed the filling is achieved, but also that the G FI __ temperature at the deeper level rises to 25 - 30°C before the application of heat via the compressed air stream and floor surface is broken off. The heating and drying procedure can require a time of some days before the desired values are obtained. The temperature of the compressed air stream, which is still supplied dehumidified, is subsequently lowered to accelerate the moisture migration from below to the dried-out area, i.e. the sand filling 4, flooring 5 and the upper portion of the concrete slab 1. The floor surface heating is simultaneously broken off or reduced. The compressed air supply temperature is preferably reduced to the order of magnitude +10 C. The dried and colder compressed air stream is maintained until the moisture under the concrete slab 1 or in the concrete close to the underside of the slab has dropped to a predetermined second value, indicating that desired drying of the area in or below the concrete has also been achieved. Measurements in this area are suitably made through the previously-mentioned hole under the threshold. The compressed air supply can be broken off when the temperature has dropped to 15 - 17 C and the relative humidity of the air has dropped to about 70 % in this area. This cooling process can also take some days to carry out. Should it be found that the relative humidity does not sink to the desired level, after a fairly long compressed air supply time, selected by experience, the whole of the described heating and cool¬ ing cycle is repeated until this desired final state is arrived at. To achieve as uniform drying-out as possible over the entire floor area, it may be further suitable to vary the compressed air stream flow paths during the described heating and cooling procedures in the following manner. During the introductory phases, at least, of both cycles, the compressed air stream is supplied through all the holes 7 made in the flooring in Figure 2, there being thus obtained for the entire floor area a flow picture of the kind indicated to the left of the chain-dotted line in the Figure, i.e. from the centre and out towards the edges for departure via all the gaps 8. During the- terminating phases of either or both cycles, all the gaps 8 except one can be taped over. If the gap 8 along the wall with the door opening is left open, and compressed air only supplied through the row of holes 7 farthest therefrom, the flow pattern indicated to the right of the chain-dotted line in Figure 2 is obtained for the entire floor surface. By these measures there is thus obtained a longer flow path for the air stream, which with great probability thus finds other flow paths than previously and will pass through previously possibly insufficiently aired portions. The room where the floor is being dried is suitably provided with temporary apparatus , known per se, for improving ventilation, so that damp air and excess heat is led from it. The apparatus partially described hereinbefore for carrying out the method in accordance with the invention is schematically illustrated in Figure 3. The compressed air source 13 supplying dehumidified compressed air to the tubes 10 via the hoses 11, this air being also treated with respect to its temperature, comprises an air compressor 20 with a cooler 21 , a dehumidifying apparatus 22 with two alternatively connnectable or regenerable dehumidifying units, a cooling battery 23 (in circuit with a cooling compressor 24) and a heating battery 25, e.g. heated with excess heat from the cooler 21 of the air compressor 20. The mattress-like heating pad 14 for heat¬ ing the floor surface may, at least to some extent, be heated with water from the cooler 21 of the air compressor or the condenser of the cooling compressor 24.

Claims: CLAIMS 1. A method of drying a concrete floor structure (1) together with its associated filling (4) and flooring (5) , which have been damaged by moisture or water, supplyorifices (7) for an air stream being made in the floor (5) down to an air-permeable layer formed by the filling (4) , from which there are arranged outlet openings (8) , the air stream being caused to flow through the air-permeable layer until a given lowering of the moisture in the air in a relevant first measuring point (16) in communication with the air-permeable layer has been achieved, characterized in that the supply openings (7) are made in the form of a plurality of narrow holes, that a plurality of injection tubes (10) connectable to a compressed air source (13) are inserted individually in each of the narrow holes for supplying an air stream in the form of a compressed air stream, in that a heater (14) adapted for heating the floor area is placed on or above the floor, that the air stream with low absolute humidity and substantial excess temperature in relation to the initial temperature of the floor structure (1) is supplied to the air-permeable layer (4) via the injection tubes (10) until the humidity of the air at the first measuring point (16) has fallen to a predetermined first value, that the surface of the floor (5) is simultaneously heated with the aid of the heater (14) to the same temperature as that of the air stream or higher, that the supply temperature of the air stream is subsequently lowered for accelerating moisture migration from below to the area of the air- permeable layer (4) , the floor heating preferably being reduced or interrupted, that the air stream in the condition just mentioned. is maintained until the moisture under the concrete or in the concrete close to its underside has dropped to a predetermined second value, indicating that desired drying in the area in or below the concrete has also been provided, and in that the described heating and cooling cycle is repeated, should lowering of the moisture to the predetermined second value not take place after the air stream in the last-mentioned condition has been maintained for some time. 2. Method as claimed in claim 1, characterized in that the absolute humidity of the air stream supply is kept at about 0.2 g water/m air. 3. Method as claimed in claim 1 or 2 , characterized in that the temperature of the air stream supply with the said excess temperature is kept at 30 - 50 C and that the temperature at the surface of the floor is kept about 10 C higher. 4. Method as claimed in any of Claims 1 - 3, characterized in that the temperature under the concrete or in the concrete close to its underside is also measured, and that the air stream with the mentioned excess temperature, and preferably the floor surface heating also, is maintained until the measured temperature has risen to a predetermined level, preferably 25 - 30 C, the temperature of the air stream being first lowered after the increase to this temperature level as well as the reduction of humidity in the first measuring point to the predetermined first level has been achieved, said first value preferably being set at 60 to 65 %, measured on relative air humidity, the air stream with the temperature preferably lowered to the order of magnitude of +10 C being maintained at least until temperature measurement in, or below, the concrete indicates a temperature drop to 15 to 17 C, the predetermined second value being set to about 70 %, measured on relative air humidit . 5. Method as claimed in any of claims 1 - 4, characterized in that the narrow holes (7) are made by drilling and are given a diameter of 2 mm max, and are localised in several rows with a spacing of 10 - 50 cm, preferably about 15 cm, between the holes in each row. * 6. Method as claimed in any of claims 1 - 5, characterized in that the moisture in the air at the first measuring point (16) is measured in a cavity under a threshold, said cavity being in communication with the air-permeable layer (4) and that a drill hole has been made here in or through the concrete, said hole being used for temperature and humidity measurement in or under the concrete. 7. Method as claimed in any of claims 1 - 6, characterizedd in that the narrow holes (7) are made in central portions of the floor (5) and that the air stream is led in a direction outwards and departs via peripheral gaps (8) which have been uncovered by remov¬ ing the skirting boards, and that this flow sequence is maintained during at least the introductory phase of both the air supply with excess temperature and the subsequent cooling with colder air, while certain of these gaps (8) are covered up, e.g. by being taped over, during at least one terminating phase, the supply of air through the narrow holes (7) being restricted solely to such holes (7) which are situated at a large distance from the gaps (8) or gap still open, so that the air stream is taken a longer distance than previously under the floor for establishing flow paths through previously possibly insufficiently aired portions. 8. Apparatus adapted for drying a concrete flooring structure (1) , with its associated filling (4) and floor¬ ing (5) which have been damaged by moisture or water, with the aid of air which is taken in trhough air-permeable layers thereof, said apparatus including an air compressor (20, 21) provided with drying means (22) for the air stream, as well as a cooling battery (23) and a heating battery (25) for the air, characterized by a separate heater (14) for heating the floor surface, and a plurality of injection tubes (10) intended for insert¬ ing into narrow holes (7) in the floor (5) and adapted to be supplied with compressed air via hoses (11) . 9. Apparatus as claimed in claim 8, characterized in that the injection tubes (10) comprise piping, preferably with an outside diameter of 2 mm max, said piping having several axially spaced holes (12) in its wall. 10. Apparatus as claimed in claim 8 or 9, characterized in that the separate heater (14) comprises one or more mattress-like heating pads which are upward¬ ly covered with heat insulating, and preferably reflect- ing, material (15) and are heated with the aid of internal hot water coils or electrical coils. ■ J 'i.tAl . V li-O -

Inventors: KULLBERG BENGT GUSTAV ADOLF E, KULLBERG, BENGT
Applicants: KULLBERG BENGT GUSTAV ADOLF E, KULLBERG, BENGT
Application year: 1983
Main classification: E04B1
IPC codes: E04B1