WO2007097674A1

WO2007097674A1 - One-way valve and window with heat recovery means

Info

Publication number: WO2007097674A1
Application number: PCT/SE2006/050579
Authority: WO
Inventors: Holger Svensson
Original assignee: Nibe Ab
Priority date: 2006-02-22
Filing date: 2006-12-14
Publication date: 2007-08-30
Also published as: SE0600415L; EP1987221A1; SE530207C2; EP1987221A4

Abstract

A one-way air inlet valve (1) comprises an elongate housing (110) and a valve member (200) arranged to open at a positive differential pressure and close at a negative or zero differential pressure. The elongate member (110) comprises a valve surface (140) provided with openings (140) and arranged to cooperate with the valve member (200) such that the valve member (200) sealingly engages the valve surface (140) at zero or negative differential pressures, and disengages the valve surface (140) at positive differential pressures. The valve surface (140) is arranged with an angle of 30 to 80 degrees in relation to the horizontal plane.

Description

ONE-WAY VALVE AND WINDOW WITH HEAT RECOVERY MEANS

FIELD OF THE INVENTION

The present invention relates to a one-way air inlet valve comprising an elongate housing and a valve member. The valve member is arranged to open at a positive differential pressure and close at negative or zero differential pressure. The elongate housing comprises a valve surface provided with openings and is arranged to cooperate with the valve member such that the valve member sealingly engages the valve surface at zero or negative differential pressures, and disengages the valve surface at positive differential pressures.

Furthermore, the present invention relates to a heat recovery window. The heat recovery window comprises an inner glass surface and an outer glass surface suspended in a frame, said inner and outer glass surfaces defining between themselves a space, wherein the space on one side is connected to an inside of a building and on the other side to the outside air.

PRIOR ART

It is a long felt need to reduce the amount of energy required to heat buildings in cold areas during winter time, and the strive towards buildings requiring less heating energy has come a long way. For example, efficient insulation methods are used to minimize heat dissipation through walls and roofing; in brief, simply adding to the amount of insulation material could reduce the heat dissipating through walls and roofing. Furthermore, modern houses are very air tight to reduce heat losses due to ventilation.

Modern buildings often require a mechanical ventilation system, i.e. a system comprising a fan expelling indoor air, preferably from spaces in the building where the air is "polluted", like for example the kitchen and the restroom areas. It is also more or less a standard procedure to recover the heat in the air to be expelled, e.g. in a heat recovery heat pump. As could be understood, the air exiting the house must be replaced by air from the outside. Often, there are air intakes arranged in the vicinity of the window of the building. One major source of heat dissipation to the outside from modern buildings is the windows. Heat dissipates through the windows in two ways, namely by radiating and being conducted through the glass in the windows. One efficient way to reduce, or rather recover, heat dissipated through windows is described in SE-A-502 143. SE-A-502 143 describes a window, wherein the incoming outside air travels in a space defined by inner and outer glass surfaces in the window, prior to entering the building through an inlet. Heat dissipated from the building through the inner glass surfaces will then be used to heat the incoming air; hence, the incoming air will gain a temperature increase. As could be understood, this is an efficient way to use heat that otherwise would be lost to the outside.

There is however one problem still to be solved with the above mentioned window type; they function flawlessly when the airflow is as intended, namely inwards, i.e. from the outside of the building to the inside of the building. In case the flow of air is reversed, warm, moist indoor air will enter the space defined by the relatively cold internal and external glass surfaces. As is well known by persons skilled in the art, warm, moist air hitting a cold surface will lead to mist forming on the cold surface; obviously, mist forming on a glass surface significantly reduces the visibility through the window. Reverse flow can e.g. take place in air intakes positioned on the leeward side of a building, in case the flow in through intakes placed on the windward side exceeds the flow that is expelled from the building by the mechanical ventilation system.

One way of reducing the problem with mist buildup could be to arrange a one-way valve in the window; such a one-way valve would allow air to enter the building, but stop air from leaving the building through the inlet valves, hence effectively avoiding mist buildup. One demand is however that the one-way valve should open at a low differential pressure; otherwise, it is likely that air will enter the building in other ways, e.g. through untight window frames or the like.

Finnish utility model FI-U-20030146 describes a one-way valve, wherein a valve member rests upon a flat surface provided with openings for allowing incoming air to pass the valve by lifting the valve member. The patent does however not mention the possibility to use the valve to stop mist buildup in a window provided the function of recovery of dissipated heat; furthermore, it takes a considerable differential pressure to lift the valve member off the flat surface.

The aim of the present invention is to provide a one-way valve suitable for windows having the function of recovering dissipated heat by forcing incoming air to travel between an outer glass surface and an inner glass surface. The one-way valve according to the present invention requires a very low differential pressure to open.

SUMMARY OF THE INVENTION

The present invention solves the above and other problems by providing a one-way valve wherein a valve surface is arranged with an angle of 30 to 80 degrees in relation to the horizontal plane. In a preferred embodiment of the invention, the one-way valve comprises an elongate housing made of an extruded aluminum profile.

In a preferred embodiment, a valve member opening and closing the valve is made of lightweight material, e.g. expanded polystyrene.

In order to restrict the maximum opening area of the valve, adjustable stop means for restricting movement of the valve member could be arranged. Finally, a preferred use of the one-way air valve is for avoiding backflow of air through a window designed for recovery of dissipated heat.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention will be described with reference to the appended drawings, wherein:

Fig. 1 is an exploded perspective view of a window valve according to the present invention, Figs. 2a and 2b are section views showing the window valve according to the present invention in open and close positions, respectively,

Fig. 3 is a perspective view showing a backside of an elongate profile comprised in the window valve according to the present invention, and

Fig. 4 is a schematic view showing a window design in which the window valve according to the present invention could be used.

DESCRIPTION OF EMBODIMENTS

As stated in the "prior art" section, it is crucial for a one-way valve suitable e.g. for windows having a heat recovery function to open at very low negative differential pressures and close immediately upon a positive differential pressure. In the following, some exemplary embodiments fulfilling the requirement of opening at low differential pressures will be explained. On the drawings, like reference numerals will be used for indicating like components. Moreover, the term "negative differential pressure" will be used to describe a situation where a pressure inside a building is lower than the pressure on the outside of the building.

In Fig. 1, a window valve 1 according to the present invention is shown. The window valve 1 comprises a valve body 100, a valve member 200 and two, preferably identical, end pieces 300. Hereinafter, the design and function of the valve body 100, the valve member 200 and the end pieces 300 will be explained. The valve body 100 comprises an elongate profile 110, which preferably is extruded. The profile 110 comprises a bottom section 120, a joining section 120b, a front section 130, an inclined valve section 140, and a top section 150. The end of the bottom section 120 facing away from the front section 130 is preferably adapted to provide a tight fit to a vertically aligned portion of a window frame or the like, such that the valve body will run in a horizontal direction; the same is the case for the end of the inclined valve section 140 facing away from the front section 130. The vertically aligned portion of the window frame should be connected to the outside air.

As can be seen in Figs. 2a and 2b, the bottom section 120, the inclined valve section 140 and the front section 130 are joined by the joining section 120b. In the shown embodiment, the joining section 120b and the inclined valve section 140 meet at a right angle, i.e. the angle between the inclined section 120b and the inclined valve section 140 is about 90 degrees. In other embodiments, the angle could however be both narrower and wider. In the shown embodiment, the inclined valve section 140 has an inclination of about 60 degrees compared to the plane of the bottom section 120, i.e. the horizontal plane; this means that the inclination of the joining section 120b is about 30 degrees compared to the plane of the bottom section 120.

As can be seen in Fig. 3, the inclined valve section 140 includes openings 140', wherein the openings connect the space defined by the inclined valve section 140, the bottom section 120 and the window frame to which the valve 1 according to the invention should be attached, to the space defined by the front section 130, the inclined valve section 140 and the top section 150. The top section 150 comprises vents 160, which are mutually divided by laterally extending bridges 170; the vents 160 connect the space defined by the front section 130, the inclined valve section 140 and the top section 150 with the interior of a building in which the window is mounted.

Moreover, the window valve 1 according to one embodiment of the present invention comprises movement stoppers 110' whose function will be described later.

The valve member 200 is an elongate piece of lightweight material, e.g. expanded polystyrene (EPS) foam, polyurethane foam or any expanded or foamed plastic material. Preferably, the lightweight material has a density of about 50-200 kg/m³. The height of the valve member 200 should be such that it covers the openings 140' when an end 210 of the valve member rests on the inclined section 120b, and its length could be such that a single valve member 200 covers all openings 140' . It is however also possible to divide the valve member into smaller valve member components, wherein each component covers at least one opening 140' . The thickness of the valve member 200 should be sufficient to give enough strength; in one embodiment of the invention, a sufficient thickness is about 3-5 mm.

Preferably, the end 210 is formed with a narrow angle, since a minimal opening resistance then is achieved. The two end pieces 300 are preferably sealingly snap-fitted onto the ends of the elongate profile 110. As shown in Fig 1, the end pieces each comprise fastening holes 310; by the fastening holes 310, the end pieces, and due to the connection to the elongate profile 110, ultimately the elongate profile comprised in the window valve 1 according to the present invention, could be fastened to e.g. a window- or doorframe.

The function of the valve 1 according to the present invention is, as mentioned, to allow a flow of air in one direction, and block airflow in the other direction. According to the invention, this is achieved by the fact that a negative differential pressure (which is necessary to achieve a flow of air) will lift the valve member 200 from the inclined valve section 140 (position where the valve member sealingly engages the inclined valve section 140 shown in Fig. 2a) . When the valve member 200 has disengaged from the inclined valve section 140, it will continue to rise until it engages the movement stoppers 110', provided that the negative differential pressure is large enough. This valve member position is shown in Fig. 2b. The movement stoppers 110 could be adjustable to allow tuning of the maximum opening area; if the movement stoppers 110' extend far towards the inclined valve section 140, the maximum opening area of the window valve 1 will be limited; if the movement stoppers extend less towards the inclined valve section 140, the maximum opening area will be larger.

As mentioned, the joining portion 120b is arranged with a right angle with respect to the inclined valve section 140. This means that the joining portion is leaning towards the inclined valve section. This leaning prevents the end 210 of the valve member 200 to disengage the inclined valve section 140.

As could be understood, if a flow of air in the allowable direction, i.e. the direction emanating from a negative differential pressure, should cease or become reversed, the valve member 200 will fall back to the closing position, such as shown in Fig. 2a. In this position, the valve member will block airflow in both directions. As mentioned in the prior art section, this is very beneficial, especially for windows provided with an external glass surface, wherein intake ventilation air is drawn from a space defined by an external glass surface and an internal glass surface; if the flow of air in such windows should be reversed, severe problems with mist on the "inside" of the external glass surface would occur.

Here, it could be suitable to mention a few words about the inclination of the inclined valve section 140. The inclination is crucial in order to obtain an opening differential pressure that is as low as possible; as is known by persons skilled in the art, it takes a smaller force to lift a component already being partly lifted, i.e. leans on an inclined surface, than it does if the same component is laying flat. In the shown embodiment, the angle between the inclined valve section 140 and the horizontal plane is about 60 degrees; this inclination means that the force required to lift the valve member off the inclined valve section 140 is half the force that would be required if the valve member was laying on a flat surface. Obviously, the required lifting force could be even more reduced if the inclination was even steeper; a more steep inclination gives however a lower sealing pressure between the inclined valve section 140 and the valve member 200. Tests have shown that an inclination of about 60 degrees is a good trade-off between sealing pressure and ease of lifting the valve member. In the described embodiment of the invention, the negative differential pressure required to lift the valve member 200 from the inclined valve section 140, hence opening the valve 1 for incoming air, is about 2 Pa, i.e. 2 N/m².

A schematic example of a window 10 adapted for recovery of heat having dissipated through the internal glass surfaces is shown in Fig. 4. Air about to enter internal spaces 15 of a building is forced to pass through a space 20, defined by an internal glass surface 30 (which preferably comprises an insulated glass unit) and an external glass surface 40. Arrows A denote the airflow of air about to enter the internal spaces 15 of the building. The window valve 1 according to the present invention is arranged on a frame 50 suspending the internal and external glass surfaces 30 and 40. By this arrangement, a temperature increase of about 5-10 degrees C of the incoming air could be obtained, as compared to an air inlet valve collecting air directly from the outside, i.e without allowing the incoming air to pass the space 20 between the external and internal glass surfaces 30 and 40. The temperature increase not only reduces the energy- consumption of the building, it also gives an increased living comfort, since cold draught close to windows will be significantly reduced.

As can be understood, the most benefit from the window valve 1 according to the present invention is obtained in combination with a window designed according to the embodiment in Fig. 4, but there is nothing that excludes use of the window valve 1 in windows or doors having "direct" intake of outdoor air; such use avoids buildings being "supervented" at windy outdoor conditions due to the fact that air exits the building through intakes without one-way function at the leeward side and enters the building through intake valves at the windward side. One further advantage with the one-way valve according to the present invention is that it directs incoming air upwards; by directing the air upwards, the incoming air will be more likely to mix with indoor air, hence avoiding cold draught.

As could be understood, the valve according to the present invention could be varied significantly without falling outside the scope of the invention such as it is defined in the appended claims .

Claims

1. A one-way air inlet valve (1), comprising an elongate housing (110) and a valve member (200) arranged to open at a positive differential pressure and close at a negative or zero differential pressure, wherein the elongate member (110) comprises a valve section (140) provided with openings (140) and is arranged to cooperate with the valve member (200) such that the valve member (200) sealingly engages the valve section (140) at zero or negative differential pressures, and disengages the valve section (140) at positive differential pressures, characterized in that the valve section (140) is arranged with an angle of 30 to 80 degrees in relation to the horizontal plane.

2. The one-way valve (1) according to claim 1, wherein the elongate housing (110) is an extruded aluminum profile .

3. The one-way valve (1) according to claim 1 or 2, wherein the valve member (200) is made of lightweight material, e.g. expanded polystyrene.

4. The one-way valve (1) according to any of the preceding claims, further comprising adjustable stop means

(HO') for restricting movement of the valve member (200) .

5. The one-way valve (1) according to any of the preceding claims, wherein the valve section (140) has an inclination of 50-70, preferably 60, degrees with respect to the horizontal plane.

6. Heat recovery window (10), comprising an inner glass surface (30) and an outer glass surface (40) suspended in a frame (50) , said inner and outer glass surfaces defining between themselves a space (20) , wherein the space (20) on one side is connected to an inside (15) of a building and on the other side to the outside air, characterized by the one-way valve (1) according to any of the preceding claims being arranged to allow an airflow from the space (20) into the inside (15) of the building and block airflow in the other direction.

7. The heat recovery window (10) according to claim 6, wherein said inner glass surface is an insulated glass unit .

8. Use of the one-way air valve (1) according to any of the preceding claims for avoiding backflow of air through a window (10) arranged for recovery of dissipated heat .