Patent Description:
A problem with assembling and producing of beams is the long drying time of concrete, which is typically weeks, even months. This requires more assembling time and higher assembling costs. Furthermore, there has to be a storage room in the factory for drying of concrete, which might restrict the production capacity of beams. If a beam is filled with concrete only at the installation place, drying of concrete might delay the initiating of other operation stages.

Document <CIT> discloses a steel pipe inside of which a cylindrical hollow concrete part is placed so as to increase the strength and rigidity of the steel pipe.

Document <CIT> discloses a flue gas channel making machine comprising a frame assembly, a support assembly, an inner die assembly, a weight loss assembly, an outer die assembly, a hydraulic assembly, a water absorbing assembly and an electrical control assembly. Moisture is sucked from the raw material through the water absorbing assembly during the operation so as to achieve rapid product formation.

<CIT> discloses a beam comprising a bottom plate, two web plates and a top plate, which define a space filled with concrete.

<CIT> discloses a concrete slab with internally cast ducts for circulating gas. The ducts communicate directly with the surrounding concrete to allow migration of substances from the concrete into the ducts and removal of the same by means of the gas circulating in the ducts as well as migration of substance in the gas circulating in the ducts into the concrete.

The aim of this invention is to achieve a beam by means of which the above mentioned problems can be reduced.

The aim of the invention is achieved with a beam according to claim <NUM>, which beam comprises a base plate, two web plates and a top plate, which define a space, the space being filled with concrete. A pipe is fitted in the space, the pipe comprises a wall through which moisture can be transferred from the outside of the pipe from the concrete in the defined space to the inside of the pipe, and which pipe is arranged to be in the flow connection with the outside of the space for transferring moisture along the pipe to the outside of the space. The end of the pipe is arranged through the hole in the bottom plate to the outside of the space or connected to the hole. The other end of the pipe is arranged through the other hole in the bottom plate to the outside of the space or connected to the other hole. The hole of the bottom plate is next to the end of the beam and the other hole is next to the other end of the beam.

Significant advantages are achieved by the invention. Moisture of concrete inside of the beam is transferred to the pipe, and further along the pipe to the outside of the beam, wherein concrete can be dried faster than earlier, which for one shortens the manufacturing time of a beam at the factory or the installation time at the installation place. Drying of concrete can be made more effective by conducting pressurized air into the pipe. The pressurized air can be heated, if necessary.

In the following, the invention will be described in more detail by the aid of embodiments with reference to the attached drawings, wherein.

Slab systems of a building, such as hollow-core slabs, composite slabs and shell slabs and in-situ cast concrete slabs can be supported on a steel beam <NUM> presented in the drawings. During seam concreting or other concreting, the beam <NUM> is filled with concrete, and after the concrete has hardened, the beam <NUM> serves with concrete as a load-carrying composite structure for slab systems. The beam <NUM> is filled with concrete at the assembling place or in the factory during the manufacturing phase, and will be delivered to the assembling place ready-concreted.

Beam <NUM> comprises a base plate <NUM>, to which two web plates <NUM> are fixed, which form the sides of the beam <NUM>. The web plates <NUM> are arranged parallel at a distance from each other. The base plate <NUM> extends in lateral direction of the beam <NUM> into both sides of the web plates <NUM>, and thus forms protruding parts <NUM> for slab systems to be supported on beam. If beam <NUM> is so-called edge beam, there is only on one side of the beam <NUM> a protruding part <NUM>, on which the plate is supported.

The angle between the web plates <NUM> and the base plate <NUM> is less than <NUM>°, wherein the distance between the web plates <NUM> is smaller in upper parts of the web plates <NUM> than in lower parts. Alternatively, one web plate <NUM> can be perpendicularly against the base plate <NUM>, if beam <NUM> is a so-called edge beam.

Web plates <NUM> are connected to each other with their upper edges by a top plate <NUM>. Base plate <NUM>, web plates <NUM> and top plate <NUM> form a space <NUM>, which can be filled with concrete. Web plates <NUM> are fixed to base plate <NUM> and to top plate <NUM> by welding, for example. Alternatively, top plate <NUM> and web plates <NUM> can be formed of the same plate by bending. The ends of beam <NUM> can be closed by end plates <NUM>. There are concrete feeding openings <NUM> in web plates <NUM> through which feeding openings <NUM> concrete is fed into the space <NUM> defined by base plate <NUM>, web plates <NUM>, and top plate <NUM>. Moreover, there are air venting openings <NUM> in the upper parts of web plates <NUM> for removing air from the space <NUM> during concreting.

Beam <NUM> comprises longitudinal fire steels <NUM>, which are arranged in the space <NUM>. In an embodiment according to drawings fire steels are fixed on their place by steel bands. Steel bands are looplike. Alternatively, fire steels can be placed to be supported by supports fixed to base plate <NUM> of the beam. Supports <NUM> are placed at regular intervals in the longitudinal direction of the beam <NUM>. Fire steels <NUM> are fixed to supports with seal bands <NUM>, for example. Moreover, fire steels <NUM> are placed on top surface of the top plate <NUM> of the beam and to corners between top plate <NUM> and web plates <NUM> in space <NUM>. Fire steels <NUM> are corrugated bars.

One or more pipes <NUM> are arranged in the space <NUM>, which comprises a moisture-permeable wall, through which moisture, such as water and/or steam, is arranged to transfer. In <FIG>, pipe <NUM>, which has been placed in the space <NUM>, is illustrated with dotted lines in order to illustrate the location of the pipe <NUM>. Moisture is arranged to transfer from the outside of the pipe <NUM>, i.e. from concrete in the space <NUM> to the inside of the pipe <NUM>. This can be provided so that there are holes <NUM> in the wall of the pipe <NUM>, through which holes <NUM> moisture can transfer through the wall. Holes <NUM> are placed at a distance from each other in the longitudinal direction of the pipe <NUM> and in the direction of circle. Typically, holes <NUM> are placed over the length of the whole pipe <NUM>. Diameter of holes <NUM> is less than <NUM>, typically less than <NUM>. The pipe <NUM> is of plastic, or of other material suitable for the purpose. A drainage pipe, for example, can be used as a pipe <NUM>. Alternatively, or addition to the holes, the pipe <NUM> can be made of moisture-permeable material. The pipe <NUM> can be a drainage pipe without holes, for example, through the wall of which moisture permeates from the outside of the pipe <NUM> to the inside of the pipe <NUM>. The inner diameter of the pipe <NUM> is at least <NUM>, typically at least <NUM>.

The pipe <NUM> is in the longitudinal direction of the beam <NUM>. The horizontal part of the pipe <NUM> is parallel to the longitudinal axis of the beam <NUM>. Advantageously, the horizontal part of the pipe <NUM> is placed in vertical direction in the center of the space <NUM>, wherein the lateral force influencing on the pipe <NUM> is smallest. The pipe <NUM> is placed in horizontal direction in the center of the space <NUM>. The pipe <NUM> is fixed or supported on fire steels <NUM>, seal bands of fire steels or supports or concrete feeding openings <NUM>, for example.

The inner part of the pipe <NUM> is arranged to be in the flow contact with the outside of the space <NUM> for transferring moisture along the pipe <NUM> to the outside of the space <NUM>. The flow contact with the inner part of the pipe <NUM> and with the outside of the space <NUM> can be provided e.g. so that in the plate, such as a bottom plate <NUM>, of the beam defining the space <NUM>, there is a hole <NUM> through which the end of the pipe is arranged or to which the end of the pipe <NUM> is connected with the help of a pipe fitting, for example. Additionally, in the plate, such as a bottom plate <NUM>, of the beam defining the space <NUM>, there is another hole <NUM>' through which the other end of the pipe is arranged or to which the other end of the pipe <NUM> is connected with the help of the pipe fitting, for example. The end/ends of the pipe <NUM> can be provided with valves, with which the air flow in the pipe <NUM> can be regulated and the pipe <NUM> can be closed.

In an embodiment according to drawings the end of the pipe <NUM> is connected to the hole <NUM> in the bottom plate <NUM>, and the other end of the pipe <NUM> to the other hole <NUM>' in the bottom plate <NUM>. Alternatively, the hole <NUM> and/or the other hole <NUM>' can locate in the upper plate <NUM> or in the web plate <NUM>. The hole <NUM> and the other hole <NUM>' are placed as close as possible to the end and to the other end of the beam <NUM>, wherein moisture transfers from concrete to the pipe <NUM> over the longest possible length. Additionally, beam <NUM> is generally supported at its ends, wherein the bending moment influencing on the beam <NUM> is smallest at the ends. Because of this the ends of the pipe <NUM> can easily be fixed to the holes <NUM>, <NUM>'.

The hole <NUM> is next to the end of the beam <NUM>. Typically, the distance of the hole <NUM> from the end is max. <NUM>/<NUM> of the length of the beam. The other hole <NUM>' is next to the other end of the beam, respectively. Typically, the distance of the other hole <NUM>' from the other end is max. <NUM>/<NUM> of the length of the beam.

Additionally, beam <NUM> comprises at least one moisture sensor <NUM> for measuring moisture content of concrete in the space <NUM>. Proportional or absolute moisture content of concrete is measured with the moisture sensor <NUM>. Additionally, temperature of concrete can be measured with the moisture sensor <NUM>. The moisture sensor <NUM> is placed in the space <NUM>, for example it is fixed to the inner surface of the upper plate <NUM>. Measurement data in the moisture sensor <NUM> is transferred wireless or with wire to a display from which the measurement data can be read.

Beam <NUM> is produced as follows. Bottom plate <NUM>, web plates <NUM> and upper plate <NUM> are fixed to each other so that they form a space <NUM>. A pipe <NUM> is arranged in the space <NUM> so that the pipe <NUM> is arranged or supported on desired place before the plates <NUM>, <NUM>, <NUM> are fixed to each other, or thereafter. Flow connection is formed between the inside of the pipe <NUM> and the outside of the space <NUM> so that water and/or vapour is able to transfer along the pipe <NUM> to the outside of the space <NUM>. The end and/or the ends of the pipe <NUM> are connected to the first hole <NUM> and/or to the other hole <NUM>', or are arranged through the first hole <NUM> and through the other hole <NUM>' to the outside of the space <NUM>. The moisture sensor <NUM> is fixed to the inner surface of the upper plate <NUM>. The ends of the space <NUM> are closed with end plates <NUM>. Concrete is fed into the space <NUM> through concrete feeding openings <NUM>. Moisture (water and/or vapour) in concrete is transferred from concrete through the wall of the pipe <NUM> to the inside of the pipe <NUM>. Moisture is transferred along the pipe <NUM> to the outside of the space <NUM>.

If it is desired to make the transfer of moisture from concrete to the pipe <NUM> more effective, air is conducted through the pipe <NUM> with a blower. The pressurized air is then conducted from the outlet to the pipe <NUM>. If needed, air is heated, if for example humidity is high in the surrounding air. Alternatively, air can be sucked through the pipe <NUM> with a blower. Moisture content of concrete is measured with a moisture sensor <NUM> locating in the space <NUM>. Measurement data of the moisture sensor <NUM> is transferred wireless or with wire to a display from which measurement data is readable. When measured moisture content has been lowered to a desired value, possible air conducting with a blower through the pipe <NUM> is ended. If needed, the blower can be provided with a guiding unit, into which measuring data of the moisture sensor <NUM> is transferred, and which switches air blowing off, when measured moisture content has been lowered to a predetermined value. If needed, a heating cable can be placed in the space <NUM>, with which heating cable concrete in the space <NUM> is heated. Concrete in the space <NUM> can be cooled down, if it warms too much. This can be made by arranging a hosepipe into the pipe <NUM>, into which hosepipe cold water is led, wherein water flowing in the hose cools concrete off.

If it is noticed from the measurement data in the moisture sensor <NUM> that concrete is drying too fast, concrete in the space can be moistened. This happens so that water is led into the pipe <NUM>, for example a water hose is arranged in the pipe <NUM>, from which water hose water is led into the pipe <NUM>, from which moisture is further transferred through the wall of the pipe <NUM> into concrete in the space <NUM>. With the pipe <NUM> moisture content in concrete in the space <NUM> can be regulated by moisten and/or by drying concrete, where necessary.

The ends of the pipe <NUM> can be closed with fire-resistant mass to improve the fire resistance of the beam <NUM>.

Claim 1:
A beam (<NUM>), which comprises a bottom plate (<NUM>), two web plates (<NUM>) and a top plate (<NUM>), which define a space (<NUM>), the space (<NUM>) being filled with concrete, characterized in that a pipe (<NUM>) is fitted in the space (<NUM>), the pipe (<NUM>) comprises a wall through which moisture can be transferred from the outside of the pipe (<NUM>) from the concrete in the defined space (<NUM>) to the inside of the pipe (<NUM>), which pipe (<NUM>) is arranged to be in the flow connection with the outside of the space (<NUM>) for transferring moisture along the pipe (<NUM>) to the outside of the space (<NUM>), an end of the pipe (<NUM>) is arranged through a hole (<NUM>) in the bottom plate (<NUM>) to the outside of the space (<NUM>) or connected to the hole (<NUM>), another end of the pipe (<NUM>) is arranged through another hole (<NUM>') in the bottom plate (<NUM>) to the outside of the space (<NUM>) or connected to the other hole (<NUM>'), and the hole (<NUM>) of the bottom plate is next to the end of the beam and the other hole (<NUM>') is next to the other end of the beam.