Roof window with air supply channel

The subject of the invention is a roof window with an air supply channel arranged in the upper element of the window frame, featuring automatic adjustment of the airflow through the channel .

There is a known roof window, having a window frame and a sash turning about a horizontal axis. In the upper element of the window frame is made an air supply channel which is made using gluing properly milled strips. The inlet to the channel is located at the external side of the window, and the outlet on the inside. The longitudinal edges of the inlet and outlet openings are parallel to the edges of the upper element of the window frame, and their lengths determine the width of the air supply channel, while the length of the air supply channel is determined by the distance between the inlet and outlet openings.

Air flowing through the channel is taken from the space shielded by a profiled sheet metal element, which protects the whole window frame and mates with the flange connecting the roof window with the roofing. The profiled sheet metal element safeguards the window from atmospheric effects, especially from rain water. The outlet opening of the channel is provided with an air grate, making it possible to adjust the air flow to the room manually.

An air channel of such design meets the requirements of air replacement in apartment buildings and public buildings under conditions called normal, i.e. when the pressure difference on the opposite sides of the window does not exceed some Pa units. In case of rapid changes of the atmospheric conditions, especially under heavy rainfall with strong wind, when the pressure gradient on the window exceeds some Pa, the inflow of considerable quantities of cold air is objectionable, particularly in the heating season. Moreover, intense rainfall on the glazing generates a water mist layer which can be carried through the channel into the room. When such conditions prevail, the user of the room can manually reduce the quantity of air flowing inside, adjusting the air grate located on the channel outlet.

Known from the application PL - P 334 669 is an air catcher installed on the window frame or sash. It consists of a scoop fixed to the external surface of the window and a manually set flow adjuster, which is installed on the inner side of the window element. Between the scoop and the adjuster there is a channel made in the window element. The scoop has an arched shield, closed on the air inlet side by a sheet metal net. Inside the scoop there is a baffle suspended by its upper edge at the external side of the window element below the channel inlet opening, hanging freely by gravitation. The shield is turning due to the pressure difference on its both faces, this changing the width of the slot. Depending on the atmospheric conditions, the shield assumes such a position that through the scoop flows during a unit time a constant quantity of air, which then flows through the channel made in the window element. On the inner side of the window, the channel is provided with a manual flow adjuster, which makes it possible to the room user to adjust the inflowing air quantity manually, the adjustment range reaching from full opening to completely closing the channel outlet.

The described air catcher is an additional outfit of the window and it cannot be used in a roof window without modifying the window construction considerably. The roof window is on its external face shielded by profiled shielding elements, which mate with the flange connecting the window with the roof covering; there is also no room in the flange to install in it an additional element in the form of the scoop. Besides, the roof windows are set on roofs with various incline angles, so installing a scoop with a freely hanging baffle assuming the initial position gravitationally would necessitate manufacturing many air catcher types with different structural parameters in order to achieve such characteristics of air flow through the individual catcher, which are proper for the given slope angle of the roof window.

Known is also the window made of plastics, according to DE 19 929 133, fitted with an aerator located between the element of the window frame and the sash frame in a contact space provided for that purpose, limited by two seals. The aerator is fixed be screws to the surface of the upper element of the window frame and forms an air chamber between the window frame surface and the

bottom wall of the aerator. At the air inlet slot of the air chamber, on the side elements of the aerator, there is a swinging air flow limiter. The limiter is a streamline bent baffle connected with its counterweight. When the pressure difference on opposite sides of the window is small, the counterweight sets by gravitation the baffle in the full open position. However, when the pressure difference on both faces of the window increases so that the air stream overcomes the gravitational force of the counterweight, the baffle turns towards the bottom wall of the aerator and narrows the slot of the air inlet to the air chamber, limiting the air stream rate. When the pressure difference on both faces of the window decreases, the baffle of the flow limiter reverts by gravitation to the initial position.

The aerator according to DE 19 929 133 cannot be applied in roof windows, which are installed on roofs with various inclination angles, because the flow limiter assuming the basic position due to gravity will not operate properly, as in the case of the air catcher according to the application PL - P 334 669. Besides, applying the aerator according to DE 19 929 133 requires an adequately vast space between the element of the window frame and the element of the sash frame, limited by two seals. However, in roof windows, the space between the seals is so small, that no other element can be inserted in it.

The aim of the invention is providing a roof window with an air supply channel made inside the upper element of the window frame, in which the air flow intensity is automatically adjusted by means located inside the channel, so that the rate of air flow is optimal, irrespectively of the prevailing atmospheric conditions.

The roof window with the air supply channel according the invention has a window frame and a sash frame which turns about a horizontal axis. In the upper element of the window frame there is an air supply channel, the inlet opening of which is on the external side of the window and the outlet opening is at the inner window side. The longitudinal edges of the inlet and outlet openings are parallel to the longitudinal edges of the upper window frame element, and their length determines the width of the air supply channel, while the distance hαhiiQQn thα inlαt on/H r»ι itlαt io thα lαn/~ιth rvf thα o ir ci innlii fhonnnl

Inside the channel is set a baffle adhering by one longitudinal edge to the one inner surface of the channel and facing by the other longitudinal edge the air inlet to the channel. The lengths of the longitudinal edges of the baffle are equal to at least the width of the air supply channel, and the shorter baffle edges are longer than the spacing between the inner surfaces of the channel, with which the baffle edges mate. The baffle is installed inside the channel so that due to the reflexive elastic force it always returns to its initial position.

Air flow through the air supply channel increases the pressure difference between the opposite sides of the baffle. When the force caused by the pressure difference exceeds the reflexive force of the baffle, the baffle departs from the fixing surface towards the opposite inner surface of the channel, narrowing the clearance of the air flow channel. The greater the air flow velocity, the higher the pressure difference on the opposite sides of the baffle and the greater is the deflection of the baffle towards the opposite wall of the channel. In order to avoid complete closing of the air supply channel, the baffle should not adhere the opposite wall of the channel on the whole length of the movable edge. This can be achieved by applying spacers or by adequately shaping the movable longitudinal edge of the baffle. The change of the clearance in the air channel is inversely proportional to the air flow velocity, therefore the air flow rate remains constant and optimal, even when the flow of supply air is very intense.

The roof window according the invention is presented in embodiments shown in the drawings. The first embodiment is depicted in Fig. 1 , showing the cross section through the upper elements of the window and the air flow channel, Fig. 2 show the window frame with the uncovered inlet to the air flow channel, Fig. 3 and Fig. 4 the cross section through the air flow channel at the place where the movable baffle edge adheres to the channel wall and respectively when that edge touches the spacer.

The second embodiment of the window is presented in Fig. 5 showing the cross section through the upper elements of the window and the air channel, Fig. 6 showing the window frame with uncovered inlet to the channel, Fig. 7 - the view on/H CQλtinn rvf thα fhonnol thrv-»ι ι/~ιh thα αlomαnt l imitin/~ι ito Ci/~ι S thα WIωVλ/

and section of the channel at the place where the movable baffle edge adheres to the spacer, and Fig. 9 showing the shape of the baffle

Example I

The roof window with an air supply channel fitted with automatic adjustment of the air flow rate through the channel has a window frame 1 and a sash 2 turning about a horizontal axis. Between the window frame 1 and the sash 2 are fitted the seals 3. Inside the upper window frame element 1 there is the channel 4, the inlet opening of which is arranged on the external side of the window and the outlet opening on the inner side of the window. The longitudinal edges of the inlet and outlet openings are parallel to the longitudinal edges of the upper window frame element, and their length determines the width of the air supply channel 4, while the length of the air supply channel 4 is determined by the distance between the inlet and outlet openings.

Inside the channel 4 is fitted the elastic baffle 5, connected by a surface strip adhering on the longitudinal edge A to the surface 6 of the channel 4, while the longitudinal edge B of the baffle 5 is facing the air inlet and protrudes out of the surface 6. The lengths of the longitudinal edges A and B of the baffle 5 are equal to the width of the channel 4, and the shorter edges of the baffle are longer than the distance between the surfaces 6 and 7 of the channel 4. Along the upper edge of the surface 7 are set the spacers 8. The outlet opening of the channel 4 is shielded by the venting grate 9, which makes it possible to adjust manually the air flow into the room.

Air flowing through the channel creates a pressure difference on both sides of the baffle 5. When the pressure difference increases so much that the force acting on the baffle 5 rises above its reflexive force, the movable edge B of the baffle 5 deflects towards the surface 7, contracting the air passage slot. When the velocity of incoming air rises further, the edge B of the baffle 5 first rests on the spacers 8 and then adheres to the surface 7 between the spacers 8. In extreme conditions, the edge B of the baffle 5 adheres almost totally to the surface 7, leaving only small air passage slots at the sides of the spacers 8.

When the pressure difference on the baffle 5 decreases, it starts to return to its initial position due to the reflexive force.

The channel 4 with automatic adjustment of the air flow rate ensures that the baffle 5 starts deflecting when the required flow rate is reached, so that the quantity of air flowing in a time unit stays unchanged and optimum, irrespective of atmospheric conditions prevailing outside.

Example Il

The roof window with an air supply channel fitted with automatic adjustment of the air flow rate through the channel has a window frame 1 and a sash 2 turning about a horizontal axis. Between the window frame 1 and the sash 2 are fitted the seals 3. Inside the upper window frame element 1 there is the channel 4, the inlet opening of which is arranged on the external side of the window and the outlet opening on the inner side of the window. The longitudinal edges of the inlet and outlet openings are parallel to the longitudinal edges of the upper window frame element, and their length determines the width of the air supply channel 4, while the length of the air supply channel 4 is determined by the distance between the inlet and outlet openings.

Inside the channel 4 is fitted the elastic baffle 5, which on each end of the longitudinal edge A has a holding part 10, separated from the other longitudinal edge B by a transverse, trapezoidal cut-out. The baffle 5 is set by its edge A in the grove 11 made in the internal surface 6 of the channel 4, and the baffle edge B is facing the air inlet and protrudes above the surface 6. The holding parts 10 of the baffle 5 are pressed to the surface 6 of the channel 4 by the wedges 12, which determine the effective width of the inlet opening of the channel 4. The distance between the longitudinal edges A and B of the baffle 5 is longer than the spacing between the surfaces 6 and 7 of the channel 4. Along the upper edge of the surface 7 are set the spacers 8. The outlet opening of the channel 4 is shielded by the venting grate 9, which makes it possible to adjust the inflowing air rate manually.

Air flowing through the channel creates a pressure difference on the opposite sides of the baffle 5, which exerts an elastic reflexive force due to pressing the

holding parts 10 by the wedges 12 to the surface 6 of the channel 4. When the pressure difference increases so much that the force acting on the baffle 5 rises above its reflexive force, the edge B of the baffle 5 deflects towards the surface 7 of the channel 4, contracting the air passage slot. When the velocity of incoming air rises further, the movable edge B of the baffle 5 first rests on the spacers 8 and then adheres to the surface 7 between the spacers 8. In extreme conditions, the edge B of the baffle 5 adheres nearly totally to the surface 7, leaving only small air passages slots at the sides of the spacers 8. When the pressure difference on the baffle 5 decreases, it starts to return to its initial position due to the reflexive force.

The channel 4 with automatic adjustment of the air flow rate ensures that the baffle 5 starts deflecting when the required flow rate is reached, so that the quantity of air flowing in a time unit stays unchanged and optimum, irrespective of atmospheric conditions prevailing outside.