GB2345533A

GB2345533A - Glazing assemblies and ventilators in frame or sash of window or door

Info

Publication number: GB2345533A
Application number: GB9827365A
Authority: GB
Inventors: Arthur Stoney
Original assignee: Titon Hardware Ltd
Current assignee: Titon Hardware Ltd
Priority date: 1998-12-11
Filing date: 1998-12-11
Publication date: 2000-07-12
Also published as: GB9827365D0

Abstract

A glazing assembly in the form of a coupled sash unit (10, Fig. 1) consists of a first ventilation part 42 and a second ventilation part 44. The first ventilation part includes an outlet chamber 56 on an inner room side 57. The second ventilation part includes a weather canopy 60. A generally rectangular duct 70 is sealingly fixed to the first ventilation part 42 and also engages the second ventilation part 44. The outlet chamber 56 may be releasably pushed on to an outlet wall (86, Fig. 8) of the first ventilation part 42 containing a dust filter (122, Fig. 8). The duct 70 may be of variable width from the first ventilation part to the second ventilation part. An outlet of the chamber 56 may be defined by a perforated part cylindrical section of the chamber and may have an area at least twice as large as an inlet to the chamber 56.

Description

GLAZING ASSEMBLES AND VENTILATORS THEREFOR The present invention relates to glazing assemblies and ventilators therefor. In particular, the invention relates to ventilators which are adapted to be mounted at slots for providing ventilation between one side of a window pane (or door section) and the other, each slot being formed through or next to an elongate section consisting of one edge of a window (or door) frame or sash. The invention also relates to coupled sash window units. A coupled sash window unit includes a window frame to be fitted to an aperture in a building and at least two window sashes, each window sash being connected to the window frame, the two sashes being spaced apart in a direction perpendicular to panes of glass held by the window sashes. Coupled sash units are frequently used in relatively noisy and/or cold environments, such as might be found in cities in the Scandinavian countries, the use of two spaced sashes tending to prevent noise/heat transfer across the window unit.

It is known to provide a coupled sash unit with a ventilation slot passing through the head section of the window frame in order to provide background ventilation to the room to which the coupled sash unit is fitted. However, there is normally only enough room in the head section to provide a relatively small ventilation slot therethrough. This means that, when it is necessary to ventilate the room at a particular mass flow rate through the ventilation slot, by drawing exterior air through the slot into the room, the exterior air tends to be brought into the room at a relatively high velocity. This means that, when the exterior air is cold, cold draughts can be felt in the room and this is undesirable.

In addition, in city or other dusty environments, dust tends to be drawn into the room during such ventilation and this is undesirable.

The present invention aims to alleviate the problem of the prior art.

According to a first aspect of the present invention there is provided a ventilator comprising first and second ventilation parts, the first ventilation part being adapted to be located adjacent a first window pane and the second part being adapted to be located adjacent a second window pane which is spaced from the first window pane in a direction generally perpendicular to the plane of the first window pane, each of the first and second ventilation parts being provided with apertures for permitting airflow to pass there-through from one side thereof to the other.

Preferably, a duct is provided for connecting the first and second ventilation parts together.

Preferably, the duct is sealingly connected to entrance walls and/or around entrance apertures to each of the first and second parts.

Preferably, the duct is mounted to the first ventilation part.

Preferably, the duct comprises a generally rectangular tube.

Preferably, the duct is of variable width across the ventilator from the first part to the second part. It has the advantage that the first and second parts may be installed at different distances apart and the ventilator may be installed in window units of variable width. The duct may be telescopable to provide for variable widths, such as by having two parts which are telescopingly slidable relative to one another, e. g. one inside the other. Alternatively, the duct may have concertinaed or bellows type side walls which are flexible for permitting width variation of the duct.

Preferably, the first ventilation part is movable relative to the second ventilation part and may be pivotable or hingeable relative to the second ventilation part.

In a preferred embodiment, the first ventilation part comprises a ventilation unit adapted to be glazed in between an edge of at least one pane of glass and an inner edge of a window frame or window sash. In the most preferred embodiment the inner edge is an inner edge of a window sash.

The first ventilation part is preferably adapted to be mounted on an inner room side of the ventilator during installation.

The first part preferably includes an apertured wall and a closure member movable relative to the apertured wall for controlling airflow through the ventilator. The closure member is preferably in the form of a flap which is pivotable relative to the apertured wall. Preferably, an actuator is provided for pivoting the closure member.

In a most preferred embodiment, the first ventilation part includes a filter, preferably a dust filter. This is particularly advantageous since dust and other undesirable material may be prevented from passing through the ventilator. The dust filter may comprise a foam filter, such as a reticulated foam. The foam

may be a reticulated polyurethane foam, such as BULFKEN^S1U. Preterably, the cellular network of the foam is substantially entirely open and the ribs have a volume of about 3% of the total foam volume. The density of the foam may be from about 26-32kg per metre cubed and the porosity may be nominally approximately between 7 and 15 pours per inch. Other foams with smaller

pours may be employed, such BULPREN, S20, S30, S45, S80 or S100. These

BULPREN products are available from Recticel nLimited, Bluebell Close, Clover Nook Industrial Estate, Alfreton, Derbyshire DE55 4RD, United Kingdom.

Preferably, the dust filter is mounted in a filter housing located on one side of the first ventilation part, said one side of the first ventilation part to be adapted to be located on an interior side of the ventilator, once installed.

Preferably, the filter is removable from the first ventilation part. Preferably, where the filter is provided in a filter housing, the filter housing is removable from a main body of the first ventilation part. Preferably, the filter housing is clippingly engageable upon the main body, preferably with at least one projection on one of the housing and the main body being clippable into a recess in the other thereof.

Preferably, an outlet of the first ventilation part finds an outlet of the ventilator on an interior side of the ventilator which is defined by a curved surface.

Preferably, the outlet is defined by a curved surface of a chamber of the first ventilation part. Where a filter is provided, the chamber may comprise a housing for the filter. The outlet for first part, in a preferred embodiment, is defined by a substantially semi-circular section.

Preferably, the second ventilation part comprises a weather canopy adapted to be glazed in between an edge of at least one pane of glass and a section of a window frame or sash in which the pane of glass is mounted.

Preferably, each of the first and second ventilation parts is adapted to be glazed in between an edge of at least one pane of glass and a section of a window sash in which the pane of glass is mounted, and both of the sashes are mounted to a window frame, the two sashes being spaced apart in a direction substantially perpendicular to the pane of the window frame. Preferably, at least one of the sashes is hingeingly openable relative to the window frame.

According to a further aspect of the present invention there is provided a ventilator comprising a ventilator part which is adapted to be mounted at a slot for providing ventilation between one side of a window pane and the other side thereof, the slot being formed through or next to an elongated section consisting of one edge of a window frame or sash, the ventilation part including an outlet on one side thereof which is adapted to be located on an interior room side of a window pane, the outlet being at least partly defined by a curved surface.

Preferably, the outlet, when viewed in one direction, has a shape which includes or consists of a part cylindrical and preferably semi cylindrical section.

Preferably the curved surface is perforated. The use of a curved surface, and preferably a semi-cylindrical section, permits the outlet to be particularly large.

Therefore, when a particular mass flow rate is passed through the ventilator, the velocity at the point of the outlet is relatively low.

In a preferred embodiment, the outlet is defined by a semi cylindrical perforated wall of a chamber of the ventilation part. In another embodiment, the outlet is generally D-shaped, consisting of a semi cylindrical section joined at either end thereof to a generally straight extension section. The chamber may contain a filter, preferably a dust filter. The dust filter may be a reticulated foam type filter having any one or more of the characteristics of the filter mentioned above with respect to the first aspect of the present invention.

According to a further aspect of the present invention there is provided a ventilator comprising a ventilator part which is adapted to be mounted at a slot for providing ventilation between one side of a window pane (or door section) and the other side thereof, the slot being formed through or next to an elongated section consisting of one edge of a window frame or sash, the ventilation part including a diffuser on one side thereof which is adapted to be located on an interior room side of a window pane (or door section). The diffuser may thereby slow the velocity of air passing through to the ventilator. The diffuser may comprise a chamber on one side of the ventilator part. The chamber may contain a filter.

According to a further aspect of the present invention there is provided a ventilator comprising a ventilation part which is adapted to be mounted at a slot for providing ventilation between one side of a window pane (or door section) and the other side thereof, the slot being formed through or next to an elongate section consisting of one edge of a window (or door) frame or window sash, the ventilation unit including an outlet chamber which is adapted to be located on an interior room side of a window pane, the chamber having an inlet one side thereof and an outlet to the room on the other side thereof, the outlet having a cross-sectional air flow area larger than the cross-sectional area of the inlet thereto.

According to a further aspect of the present invention there is provided a ventilator comprising a ventilation part which is adapted to be mounted at a slot for providing ventilation between one side of a window pane (or door section) and the other side thereof, the slot being formed through or next to an elongate section consisting of one edge of a window (or door) frame or window sash, the ventilation unit including an elongate outlet chamber which is adapted to be located on an interior room side of a window pane, the chamber having, when viewed from one direction, an inlet side and an outlet side; the inlet side having a dimension (e. g. height or distance in a direction parallel to the window pane) X, the outlet having a perimeter which is longer than %. Preferably, the perimeter is more than 1.5 times longer than %, about 1.5 to 3 or 2 to 3 times longer being typical. Preferably, the perimeter is more than 2 times longer than X.

According to a further aspect of the present invention there is provided a ventilator comprising a ventilation part which is adapted to be mounted at a slot for providing ventilation between one side of a window pane (or door section) and the other side thereof, the slot being formed through or next to an elongate section consisting of one edge of a window (or door) frame or window sash, the ventilation unit including an outlet chamber which is adapted to be located on an interior room side of a window pane, the chamber having an inlet one side thereof and an outlet to the room on the other side thereof, the outlet having at least one or a series of outlet apertures having a total cross-sectional area at least as large as 10,000 square millimetres, Preferably the total outlet crosssectional area is at least 14,000 or 15,000, more preferably at least 20,000 square millimetres. The total outlet cross sectional area may in some cases be at least 30,000 or 35,000 square millimetres. Typically 20,000 to 100,000, more typically 30,000 to 60,000, square millimetres may be employed, 35,000, 46,000 and 58,000 square millimetres being some examples.

Preferably, the outlet area is at least twice as large as and preferably at least three times as large as the inlet, about five times as large being one example.

The inlet may be located at a generally flat wall of the ventilation part having a series of ventilation apertures there-through and the ventilation part may include a closure member, preferably in the form of a pivotable flap, for restricting airflow through the apertures. Preferably, the outlet is defined by an elongated perforated part cylindrical and preferably semi cylindrical section of the chamber. The perforated section may be in the form of a mesh, the mesh conveniently being formed of metal or of plastics or of other suitable material.

According to a further aspect of the invention there is provided a glazing system comprising a first window pane and a second window pane which is adapted to be generally parallel to and spaced from the first window pane in a direction generally perpendicular to the first window pane, each of the window panes being mounted in respective first and second window frames or window sashes, and a ventilator as set out in one of the above mentioned aspects of the invention mounted to at least one of the panes. In the case of the ventilator of the first aspect of the invention, the first ventilation part of the ventilator may be located at the first of the window frames or sashes and the second ventilation part may be located at the second of the window frames or sashes.

The glazing system may comprise a coupled sash unit, the coupled sash unit comprising a window frame and two window sashes mounted to the frame, the window sashes being spaced apart in a direction substantially perpendicular to panes of glass in the sashes, when the sashes are closed. Preferably, one or both of the sashes is openable, such as by hinging, relative to the window frame and may be mounted thereon by hinges.

At least one of the sashes or frames may contain a double glazed window pane unit. At least one of the sashes or frames may contain a single pane of window glazing. In a coupled sash unit, an inner sash of the unit may contain a double glazed window unit and an outer sash may contain a single pane of window glazing.

Alternatively, each of the respective window frames or sashes may comprise a double glazed unit.

In another embodiment, one of the window panes or sashes comprises a double glazed seal unit and the second of the window frames or sashes comprises a secondary glazing unit.

The present invention also envisages any combination of the features of the aspects thereof and preferred features thereof which is not specifically recited herein. In particular, the preferred features of each aspect discussed herein are applicable to each of the others aspects hereof.

The present invention may be carried out in various ways and several glazing systems and ventilators in accordance with the invention will now be described by way of example with reference to the accompanying drawings, in which: Figure I shows a schematic view from above of a preferred glazing system in accordance with a preferred embodiment of the present invention, the glazing system being in the form of a coupled sash unit; Figure 2 is a schematic side view of part of the coupled sash unit; Figure 3 is an exploded perspective view of various parts of the coupled sash unit; Figure 4 is an exploded side view of a number of parts shown in Figure 3; Figure 5 is a side view of part of a first ventilation part of a ventilator of the coupled sash unit, with a flap thereof in a closed position; Figure 6 is a view corresponding to figure 5, but showing the flap in an open position thereof; Figure 7 is an exploded perspective view corresponding to Figure 5, showing detail of an actuator for pivoting the flap; Figure 8 is a schematic part side view of the ventilator of the glazing system; Figure 9 shows part of the ventilator of Figure 8, but with the ventilation flap thereof in an open position; Figure 10 is a view of a second preferred embodiment, corresponding to Figure 8; Figure 11 is a schematic isometric view of a filter chamber of the embodiment of Figure 10 ; Figure 12 is a schematic representation of a test rig for the embodiment of Figure 10; and Figure 13 is a view of a third preferred embodiment, corresponding to Figure 8 and 10.

Referring to Figure 1, a preferred embodiment of a glazing system in the form of a coupled sash unit 10 in accordance with the present invention is shown fitted in a rectangular aperture 12 formed through an exterior wall 14 of a building 16.

It will be appreciated that Figure 1 is a view of the coupled sash unit 10 from above.

The coupled sash unit 10 includes a window frame 18, an outer window sash 20 located on an exterior side 22 of the window frame 18 and an inner window sash 24 located on an inner side 26 of the window frame. The outer window sash 20 is fixed closed but may be openable in a conventional manner in other embodiments.

The inner window sash 24 is mounted to the window frame 18 by hinges 28 and on operation of a window handle 30 the inner window sash 24 may be rotated open by pulling the handle 30 in the direction A shown in Figure 1 so as to rotate the inner window sash open about the vertical axis 32 formed by the hinges 28. Each of the sashes 24,20, may once installed be fixed closed, or may be openable, such as by sliding or hinging.

As shown in the side view of Figure 2, a ventilator 40 of the coupled sash unit 10 consists of a first ventilation part 42 and second ventilation part 44.

The first ventilation part 42 comprises an elongate housing 46 which is glazed in between an upper head section 48 of the inner window sash 24 above the housing and the top edge 50 of a double glazed glazing unit 52 having two window panes 54 below the housing.

The first ventilation part 42 includes an outlet chamber 56 on an inner room side 57 thereof, the purpose of which will be discussed below.

The second ventilation part 44 includes a weather canopy 60 and is glazed in between an upper head section 62 of the outer window sash 20 and the top edge 63 of a single window pane 64.

Peripheral seals (not shown) of a conventional nature are provided for glazing in the window panes 64,54 and first 42 and second 44 ventilation parts, and for sealing the outer window sash 20 and inner window sash 24 to the window frame 18, as well as for sealing the window frame 18 inside the rectangular aperture 12 in the exterior wall 14.

A generally rectangular duct 70 is sealingly fixed to the first ventilation part 42 and also engages the second ventilation part 44, being engaged thereagainst and sealed thereto by a flexible resilient peripheral seal 72 which extends around a rectangular entrance 74 to the duct 70.

Referring to Figure 3, which is an exploded view of part of the ventilator, it will be seen that the elongate first ventilation part 42 has a generally rectangular cross section. A series of apertures 80 are provided passing through a generally vertical inlet wall 82 of the first ventilation part and a corresponding series of apertures 84 are provided formed through a generally vertical outlet wall 86 of the first ventilation part. A flap 88, more clearly shown in Figure 4 is joined at a top edge 90 thereof by a hinge 92 to the outlet wall 86 of the first ventilation part. An end cap 94 is provided at either end of the first ventilation part 42. The duct 70 has an outlet flange 96 which is sealingly secured to the inlet wall 82 of the first ventilation part 42 by screws (not shown), adhesive or other conventional fastening means. The flange 96 is sealed to the unit wall 82 around the apertures 84.

The duct 70 is provided at an exterior side thereof with a peripheral flange 100 to which a resilient flexible peripheral seal 102 is attached. The duct has a cross-sectional airflow area of about 10,000 square millimetres.

The seal may be pushed against a generally vertical barrier wall 104 of the second ventilation part, being sealingly engaged about a series of apertures 106 formed through the barrier wall 104.

In addition to the barrier wall 104, the second ventilation part 44 includes a hood 108, forming the weather canopy 60. The hood 108 is held to the barrier wall 104 by end caps 110 and the end caps are secured to the barrier wall 104 in a conventional manner, such as by screws (not shown) to hold the barrier wall 104, hood 108 and end caps 110 together.

The outlet chamber 56, as shown in Figure 8, has upper 112 and lower 114 beads which clippingly engage in respective elongate upper and lower channels 116,118 formed in the outlet wall 86 of the first ventilation part 42.

The outlet chamber 56 may be releasably pushed on to the outlet wall 86 of the first ventilation part, with a dust filter 122 formed of a block of BULPREN S 10 reticulated foam (which has been found to be particularly useful for filtering dust and other undesirable material from airflows) located therein. At appropriate service intervals, the outlet chamber 56 may be removed from the rest of the first part 42 by pulling on a snib 124 thereof in direction B shown in Figure 8 and the filter 122 may therefore conveniently be inspected and cleaned or replaced, as appropriate. This is an especially convenient arrangement, because the filter may very easily be serviced by a person from the inside of the building 16.

As shown in Figure 3, the outlet chamber 56 includes a generally vertical outlet wall 126 which is provided with a series of outlet apertures 128 thereon.

Likewise, upper 130 and lower 132 outlet walls of the outlet chamber are provided with respective upper 134 and lower 136 series of outlet apertures.

Therefore, airflow may pass into the ventilator 40 under the hood 108, through the apertures 106, the duct 70, the apertures 84, the dust filter 122, and into the building 16 through the outlet apertures 128,134,136. The combined area of the apertures 128,134,136 in the chamber 56 is about 14,000 to 15,000 square millimetres. The narrowest airflow point across (or bottleneck of) the ventilator is at the point (even in the open position) where the airflow passes between the flap 88 and the wall 86. The airflow area here, with the flap fully open is about 5,000 square millimetres. Preferably, the area of the narrowest airflow point across the ventilator is at least 4,000 to 5,000 square millimetres and may be substantially more. It will be noted therefore that this airflow path is sealed from the internal space 138 of the glazing system 10 which is formed between the inner sash 24 and outer sash 20, around the duct 70. This is an exceptionally beneficial arrangement. First, no dust or other undesirable material passing through the ventilator 40 enters the internal space 138 and this means that it is very infrequently necessary to clean inside the internal space 138. In addition, the duct tends to allow a relatively high mass flow rate of ventilation through the ventilator, without the ventilator being too large.

Previously, coupled sash units have incorporated a single elongate slot formed directly through the window frame thereof-equivalent to the window frame 18 shown in figure 2-and to achieve a desired mass flow rate of ventilation, the small area of the slot and outlet of the prior art ventilator has resulted in a high velocity of the airflow passing through the ventilator into the room, causing uncomfortable draughts. However, as will be clear from Figures 2 and 3, the present embodiment enables the total outlet area provided by the apertures 134, 128,136 to be substantially larger than in the prior art, so that, at a given mass flow rate, the velocity of air passing into the building 16 from the ventilator 40 may be lower. It is believed that it is not until the present application of the present applicants that it has been realised that a large outlet area can be beneficial; one would normally expect a larger item to be disadvantageous due to various reasons including cost considerations.

In addition, the airflow is filtered by the dust filter 122 which can very conveniently be serviced from inside the building 16.

It will be appreciated from Figures 4 and 8 that the flap 88 may be pivoted about the hinge 92 to vary the amount of air flowing through the ventilator.

Figure 8 shows a closed position of the flap 88 in which a lower seal 150 thereof seals against the outlet wall 86 to minimise airflow through the ventilator 40. However, Figure 4 shows an open position of the flap 88.

As shown by Figures 5,6 and 7, an actuator 152 for the flap 88 is provided by a driving adaptor 154, a cam slider 156 and an operating lever 159. The cam slider 156 has a peg 158 which passes through a bore 160 through the end cap 94 and is secured in a bore 162 of the operating lever 158. The driving adaptor 154 has a drive section 164 which fits in a corresponding drive slot 166 of the flap. It will be appreciated that, as the operating lever 159 is rotated about the axis formed by the bore 160, the cam slider 156 also rotates and through the peg 168 and slot 170 engagement of the cam slider 156 and driving adaptor 154, the flap 88 is rotated. A friction web 172 is provided on the end cap and engages one end 174 of the cam slider 156 for holding the flap 88 in a chosen position, such as the closed position of Figures 5 or 8 and the fully opened position of Figure 6. Figure 9 also shows the flap 88 in the open position.

The channels 180 shown on the first 42 and second 44 ventilation parts enable these parts to be attached to the end caps 94 by screws (not shown) fastened through holes in the end caps 94,110 into the channels 180.

Dependent upon the thickness of the glazing units 152/window panes 54,64, the width of the glazing channels 190,192 formed on the lower edges of the first 42 and second 44 ventilation parts may be varied, dependent upon the application, as required.

For example, the channel 190 of the first ventilation part 42 which would normally be a part separate from the outlet wall 86 may be selected dependant upon the application, as may be the width of the top portion 194 of the first ventilation part 42. It will be appreciated that, as shown by Figure 9, the section of the chamber or main body 196 of the first ventilation part 42 may be defined by the outlet wall 86, the top portion 194 and the inlet wall 82, including the channel.

It will be appreciated that the outlet chamber 56 is closed at the ends thereof by wing portions 198 of the end caps 194.

While the ventilator may be constructed in various ways, it is envisaged that the outlet chamber 56, outlet wall 86, channel 190/inlet wall 82, top portion 194, barrier wall 104 and grid 108 may each be formed by extrusion, such as of aluminium or plastic. The apertures 128,136,134,84,106 may be formed by punching. The end caps 94,110, the duct 70 and the lever 159, cam slider 156, driving adaptor 154 can conveniently be moulded, such as from plastics. The flap 88 may preferably be extruded. The seals 150,102 are preferably formed of soft material in a conventional manner, such as by extrusion or moulding.

The tube 70 may comprise two or more telescopable parts for accounting for different distances between the panes 54,64 in different applications, and may incorporate locking means for locking the tube at a selected width. In other embodiments, the tube may be concertinaed and flexible to achieve similar versatility.

A second preferred embodiment will now be described with reference to Figures 10 and 11 and this embodiment is identical to the embodiment disclosed with reference to Figure 1 to 9, apart from the following: Essentially, the filter 56 of the first embodiment of rather rectangular form is replaced with the filter chamber 200 which has a semi cylindrical shape. The filter chamber 200 includes a curved BULBREN S10 filter block 100'.

To accommodate the semi cylindrical filter chamber 200, the wings 198 of the end cap 94 are modified to have a semi circular shape, corresponding to the shape of the filter chamber 200.

The filter chamber has an inlet portion 201 which is defined by the apertures 84 in the outlet wall 86. The filter chamber has an outlet 202 defined by a series or grid 204 of apertures 206 formed between the bars 208 of a mesh 210. In one working embodiment, the mesh 210 is a metal mesh, but, in other embodiments, the mesh may be formed of plastics, such as by moulding. Such is the substantially open nature of the mesh 210 that the curved surface 212 of the outlet 201 is taken up more than 50% by the open apertures 206. So, the total airflow area of the outlet 202 is relatively substantial. The proportion of the curved outlet surface 212 open with apertures 206 is preferably more than 50%, more preferably more than 60%, typically more than 75%, for example, about 80-95% of the total area of the curved surface 212. This means that ventilation at a particular mass flow rate passing into the building 16 through the ventilator 40 will pass into the building 16 through the curved surface 212 relatively at a relatively low velocity. Therefore, cold incoming air will move slowly into the building and thus will have sufficient time to be warmed by the internal air of the building before being felt by persons in the building.

In the embodiment of Figures 10 and 11, the total area of the apertures 84 in the outlet wall 86 is about 5,500 square millimetres, but the open outlet area of the outlet 202 is substantially larger-about 35,000 square millimetres. Preferably the open area of the outlet of the first ventilation part 42 is at least 10,000, preferably 15, 000, typically 20,000 to 100,000 square millimetres, with more than 30,000 and most preferably at least 35,000 or 40,000 square millimetres being preferred; some examples are about 15,000,35,000,45,000 and 60,000 square millimetres respectively. It will be understood that a relatively large surface area is preferred to minimise draughts.

The curved nature of the outlet 202 is also advantageous in that airflow is dispersed at least partly omni-directionally into the building 16. Therefore, air flows and hence draughts are not concentrated in any particular zone of the building.

The building may be provided with an extractor fan distant from the glazing system for extracting air from the building and therefore causing replacement air to be drawn in through the ventilator.

When viewed in end view, as in Figure 10, the perimeter of the outlet surface 212 is about 1.57 or 1.6 times the height of the chamber 200 at an entrance thereto. The chamber therefore acts as a diffuser.

The embodiment of Figure 10 and 11 was set up on the test rig shown (not to scale) in Figure 12. The test rig consisted of a sealed chamber 300 having an extractor fan 302 for drawing air out of the chamber 300. The ventilator was set up on the coupled sash unit (not shown in Figure 12) on one wall 304 of the chamber, with the filter chamber 200 facing into the chamber 300. The chamber was 2.4 metres tall. The chamber temperature was 21 degrees Celsius and the atmospheric temperature outside the chamber was 18.9 degrees Celsius.

Atmospheric pressure was 1013. 5 millibars.

A wind velocity sensor (not shown) was placed centrally in front of the filter chamber 200 at three positions, position 1 being 500 mm in front of the front point 306 of the ventilator and 395 mm above the front point 306, position 2 being level with and 500 mm in front of the front point 306 and position 3 being 340 mm below and 500 mm in front of the front point 306.

Table 1 below shows the air velocity measured in metres per second for various pressure differentials ("PA", i. e. Pascals) across the ventilator.

TABLE 1 Position 1

PA M/Sec 50 0.1 - 0.3 100 0.4 - 0.5 150 0.5 - 0.6 200 0.5 - 0.6 250 0.6 - 0.8 300 0.7 - 0.9 Position 2

PA M/SeC SO 0 100 0 150 0 - 0.05 200 0 - 0.1 250 0 - 0.15 300 0 - 0.15 Poson

PA M/Sec 50 0 100 0-01 150 0-015 200 0.1 - 0.2 250 0.1 - 0.2 300 0.1 - 0.25 It will be noted that the fastest air velocity recorded was 0.7 to 0.9 m/s at position 1 at 300 Pascals. This arrangement was considered highly satisfactory.

With air drawn out of the chamber at 8 litres/second, the velocity of air 500mm in front of the front point was found to be about or less than 1.5 m/s.

Figure 13 shows a further ventilator 400 which has yet another elongate filter chamber 402. Like the ventilator of Figure 10, the overall ventilator 400 of Figure 13 may be installed in the same way as the ventilator of Figures 1 to 9 in a coupled sash unit. The ventilator 400 is identical to the ventilator of Figure 10, apart from the following: The filter chamber 402 has a curved or semi cylindrical portion 404 which merges at either end (top and bottom as shown) 406 thereof into a generally flat extension portion 408. In the end view of Figure 13, the extension portions are therefore shown as generally straight. The diameter of the semi cylindrical portion 404 is about 60 millimetres and the continuing length of each of the extension portions 408 is about 15 millimetres. The extension portions 408 are perforated, in the form of a mesh, like the mesh 410 of the semi cylindrical portion. The mesh is about 80% to 95% open so as to provide a substantial cross sectional area for airflow entering the building 16 from the ventilator 400.

The effective length of the filter chamber 402 is about 370 millimetres. The open outlet cross sectional area formed by the apertures (not shown) of the mesh of the semi cylindrical portion 404 and extension portions 408 is about 40,000 to 46,000 square millimetres. It will be seen that the filter chamber 402 contains a generally C-shaped block of reticulated foam 412. The foam is Bulpren S 10 and acts as a dust filter. It will be seen that the filter chamber 402 is generally D-shaped. In the end view of Figure 13, the perimeter of the outlet, made up of the semi cylindrical portion 404 and extension portions 408 is about twice as long as the height of the filter chamber at its inlet side 414. In other embodiments, the extension portions 408 could be lengthened to be about 25 or 30 millimetres long, instead of 15 millimetres long (in end view) and could be even longer.

The filter chamber 402 (and the filter chamber 200 of Figure 10) is releasably clippingly engaged on the main body of the ventilator part 42.

Various modifications may be made to the above described embodiments without departing from the scope of the invention. In particular, instead of fitting the ventilators described on coupled sash units, they may equally well be applied to a pair of spaced double glazing units, or in a system having one double glazed sealed unit spacing from secondary glazing.

Claims

CLAIMS 1. A ventilator comprising first and second ventilation parts, the first ventilation part being adapted to be located adjacent a first window pane and the second part being adapted to be located adjacent a second window pane which is spaced from the first window pane in a direction generally perpendicular to the plane of the first window pane, each of the first and second ventilation parts being provided with apertures for permitting airflow to pass therethrough from one side thereof to the other.
2. A ventilator as claimed in claim 1 in which a duct is provided for connecting the first and second ventilation parts together.
3. A ventilator as claimed in claim 2 in which the duct is sealingly connected to entrance walls and/or around entrance apertures to each of the first and second parts.
4. A ventilator as claimed in claim 2 or claim 3 in which the duct is mounted to the first ventilation part.
5. A ventilator as claimed in any one of claims 2 to 4 in which the duct comprises a generally rectangular tube.
6. A ventilator as claimed in any one of claims 2 to 5 in which the duct is of variable width across the ventilator from the first part to the second part.
7. A ventilator as claimed in any preceding claim in which the first ventilation part is movable relative to the second ventilation part.
8. A ventilator as claimed in any one of claims 1 to 7 in which the first ventilation part comprises a ventilation unit adapted to be glazed in between an edge of at least one pane of glass and an inner edge of a window frame or window sash.
9. A ventilator as claimed in any preceding claim in which the first ventilation part is adapted to be mounted on an inner room side of the ventilator during installation.
10. A ventilator as claimed in any preceding claim in which the first part includes an apertured wall and a closure member movable relative to the apertured wall for controlling airflow through the ventilator.
11. A ventilator as claimed in claim 10 in which the closure member is in the form of a flap which is pivotal relative to the apertured wall.
12. A ventilator as claimed in any preceding claim in which the first ventilation part includes a filter.
13. A ventilator as claimed in claim 12 in which the filter comprises a dust filter.
14. A ventilator as claimed in claim 13 in which the dust filter comprises a foam filter.
15. A ventilator as claimed in claim 14 in which the filter comprises a reticulated foam filter.
16. A ventilator as claimed in claim 13 in which the cellular network of the foam is substantially entirely open and the ribs have a volume of about 3 % of the total foam volume.
17. A ventilator as claimed in any one of claims 13 to 16 in which the density of the foam is from about 26 to 32 kg/m cubed.
18. A ventilator as claimed in any one of claims 13 to 16 in which the porosity of the foam is nominally approximately between 7 and 15 pores per inch.
19. A ventilator as claimed in any one of claims 13 to 18 in which the dust filter is mounted in a filter housing located on one side of the first ventilation part, said one side of the first ventilation part being adapted to be located on an interior side of the ventilator, once installed.
20. A ventilator as claimed in any one of claims 12 to 19 in which the filter is removable from the first ventilation part.
21. A ventilator as claimed in any one of claims 12 to 20 in which the filter is provided in a filter housing, the filter housing being removable from a main body of the first ventilation part.
22. A ventilator as claimed in claim 21 in which the filter housing is clippingly engageable upon the main body with at least one projection on one of the housing and the main body being clippable into a recess in the other thereof.
23. A ventilator as claimed in any preceding claim in which an outlet of the first ventilation part defines an outlet of the ventilator on an interior side of the ventilator which is defined by a curved surface.
24. A ventilator as claimed in claim 23 in which the outlet is defined by a curved surface of a chamber of the first ventilation part.
25. A ventilator as claimed in claim 23 or claim 24 when dependent upon claim 12 in which the chamber comprises a housing for the filter.
26. A ventilator as claimed in any preceding claim in which the second ventilation part comprises a weather canopy adapted to be glazed in between an edge of at least one pane of glass and a section of a window frame or sash in which the pane of glass is mounted.
27. A ventilator as claimed in any preceding claim in which each of the first and second ventilation parts is adapted to be glazed in between an edge of at least one pane of glass and a section of a window sash in which the pane of glass is mounted, and in which both of the sashes are mounted to a window frame, the two sashes being spaced apart in a direction substantially perpendicular to the pane of the window frame.
28. A ventilator as claimed in claim 27 in which at least one of the sashes is hingingly openable relative to the window frame.
29. A ventilator comprising a ventilator part which is adapted to be mounted at a slot for providing ventilation between one side of a window pane and the other side thereof, the slot being formed through or next to an elongated section consisting of one edge of a window frame or sash, the ventilation part including an outlet on one side thereof which is adapted to be located on an interior room side of a window pane, the outlet being at least partly defined by a curved surface.
30. A ventilator as claimed in claim 29 in which the outlet, when viewed in one direction, has a shape which includes or consists of a part-cylindrical section.
31. A ventilator as claimed in claim 29 or claim 30 in which the curved surface is perforated.
32. A ventilator as claimed in any one of claims 29 to 31 in which the outlet is defined by a semi-cylindrical perforated wall of a chamber of the ventilation part.
33. A ventilator as claimed in any one of claims 29 to 32 in which the chamber contains a filter.
34. A ventilator as claimed in claim 33 in which the filter is a dust filter.
35. A ventilator comprising a ventilation part which is adapted to be mounted at a slot for providing ventilation between one side of a window pane (or door section) and the other side thereof, the slot being formed through or next to an elongated section consisting of one edge of a window frame or sash, the ventilation part including a diffuser on one side thereof which is adapted to be located on an interior room side of a window pane (or door section).
36. A ventilator as claimed in claim 35 in which the diffuser comprises a chamber on one side of the ventilation part.
37. A ventilator as claimed in claim 36 in which the chamber contains a filter.
38. A ventilator comprising a ventilation part which is adapted to be mounted at a slot for providing ventilation between one side of a window pane (or door section) and the other side thereof, the slot being formed through or next to an elongate section consisting of one edge of a window (or door) frame or window sash, the ventilation part including an outlet chamber which is adapted to be located on an interior room side of a window pane, the chamber having an inlet one side thereof and an outlet to the room on the other side thereof, the outlet having a cross-sectional airflow area larger than the cross-sectional area of the inlet thereto.
39. A ventilator comprising a ventilation part which is adapted to be mounted at a slot for providing ventilation between one side of a window pane (or door section) and the other side thereof, the slot being formed through or next to an elongate section consisting of one edge of a window (or door) frame or window sash, the ventilation unit including an elongate outlet chamber which is adapted to be located on an interior room side of a window pane, the chamber having, when viewed from one direction, an inlet side and an outlet side; the inlet side having a dimension X, the outlet having a perimeter which is longer than X.
40. A ventilator as claimed in claim 39 in which the perimeter is more than 1.5 time longer than X.
41. A ventilator comprising a ventilation part which is adapted to be mounted at a slot for providing ventilation between one side of a window pane (or door section) and the other side thereof, the slot being formed through or next to an elongate section consisting of one edge of a window (or door) frame or window sash, the ventilation part including an outlet chamber which is adapted to be located on an interior room side of a window pane, the chamber having an inlet one side thereof and an outlet to the room on the other side thereof, the outlet having at least one or a series of outlet apertures having a total cross-sectional area at least as large as 10,000 sq. mm.
42. A ventilator as claimed in claim 41 in which the outlet area is at least twice as large as the inlet.
43. A glazing system comprising a first window pane and a second window pane which is adapted to be generally parallel to and spaced from the first window pane in a direction generally perpendicular to the first window pane, each of the window panes being mounted in respective first and second window frames or window sashes, and a ventilator as set out in any preceding claim mounted to at least one of the panes.
44. A glazing system as claimed in claim 43 which comprises a coupled sash unit, the coupled sash unit comprising a window frame and two window sashes mounted to the frame, the window sashes being spaced apart in a direction substantially perpendicular to panes of glass in the sashes, when the sashes are closed.
45. A glazing system as claimed in claim 44 which one or both of the sashes is openable relative to the window frame.
46. A glazing system as claimed in claim 44 or claim 45 in which an inner sash of the unit contains a double-glazed window unit and an outer sash contains a single pane of window glazing.
47. A ventilator substantially as described herein with reference to the accompanying drawings.
48. A glazing system substantially as described herein with reference to the accompanying drawings.