GB1602975A - Natural ventilators - Google Patents

Description

(54) NATURAL VENTILATORS (71) We, H. H. ROBERTSON (U.K.) LIMITED, a British Company of 27 Newgate Street, Chester CHi 1DE, and DR. D. DIL- LINGER STAHLBAU GmbH, a German Company, of 6630 Saarluis, Herving-Ford-Strasse, West Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to ventilation systems of the so-called "natural" type where air flow through a building is at least principally controlled by the heat generated in the building, i.e. is not powered by fans associated with the ventilation system.

Such ventilating system require as ventilators large, usually elongate, air-exit structures or heads above wide vents or "chimneys" through the roofs of buildings, often referred to as ridge ventilators, in order to give satisfactory ventilation in view of the large volume of air flow required at the low speeds at which it will take place.

The size of the ventilator is at least partly dictated by the width of the vent or vents and the necessity to provide for weather protection, particularly from ingress of rain water. Our cofiled application no. 52139/77 (Serial no. 1602190) provides an improved structure as to aerodynamics of air flow therethrough with such increase of efficiency as to allow significant size reductions com- pared with conventional structures. Reference is directed to that application and its claims.In preferred structures of that application, curved guides are provided at least at upper edge parts of longitudinal side walls of a throat structure if not also at upper edge parts of upwardly divergent walls of an air stream splitting structure above the throat, and curved baffles may be provided (a) from the throat into airways between the upwardly divergent walls and convexly formed outer side walls of the ventilator, and (b) with particular advantage, about the edge parts of the upwardly divergent walls where the outer side walls are convexed.

That application also refers to a provision for closing off the ventilator at its throat by pivotting of the first-mentioned curved baffles. However, access for maintenance purposes may be difficult with baffles and drive gear in the throat.

According to the present invention there is provided a natural ventilator in the form of an elongate structure to service at least one building communicating duct or passage along its length, the structure comprising outer longitudinal side walls that initially diverge from adjacent said duct or passage and then converge to upward spaced positions, an inner portion that is spaced above and covers the upper end of the duct or passage, and baffling in airways extending between the inner portion and the side walls with the baffling extending about edges of the inner portion, that baffling being adjustable to close gaps between that inner portion and upper parts of the outer side. walls.

This is most conveniently done using a single baffle in each airway that is pivotable about a position intermediate its ends, but could be achieved with multiple baffle arrangements, say after the fashion of hinged louvres.

Advantages arise from such an arrangement in that the baffle adjustment mechanism, usually motor-driven, is accessible from above, say by way of maintenance walk-ways or platforms, preferably of openwork construction, over the mouth of the head. An electric motor of the so-called linear type is preferred for the baffle drive mechanism.

One embodiment of the invention will now be specifically described by way of example with reference to the accompanying drawings, in which: Figure 1 is a section of a natural ventilator module showing its end-frame structure and pivotal upper baffles.

Figure 2 is a diagrammatic representation of a suitable drive system for the upper baffles of Figure 1; and Figure 3 is a diagrammatic plan view showing a cat-walk at junctions between ventilator modules.

As discussed in relation to Figures 1 and 2 of our copending application no. 52139/77 (Serial no. 1602190), natural ventilation systems are of substantial size compared with the building served and are usually mounted in a wide gap along the centre of a ridged roof. Louvred air entries at the lower parts of the building walls allow the heat generated within the building to "power" the ventilation system with exit air guided by the roof slopes to the ventilator structure proper, which will usually extend at least most of the length of the building and be constructed in modular sections joined together at respective adjacent end frames.

Referring specifically to Figure 1, a preferred ventilator structure has a throat 20, typically of 1 to 5 metres width, and from which outer casing walls 30 extend upwards in a generally convex shape on each side terminating at spaced positions affording a wide elongate exit mouth 32. Suitable provision is made for weathering the side walls 34 of the elongate throat to the roof of the building to be served, and there will be a space between those side walls 34 and the lower edges of the outer casing walls 30 to allow fall-through of rain water.

The throat side walls 34 extend into the outer casing and, as in our copending application, have outwardly curved terminations 36 to assist in reducing any turbulence in exit air as it is divided into two streams in airways 38 defined between the casing walls 30 and throat weathering guard 40 presenting upwardly divergent panels or walls 42 from a centrally connected position 44 above the throat to a position spaced from the casing walls 30 at or close to the position at which they begin curving towards each other. Also, the upper edges of the divergent panels or walls 41 have curved terminations or guides 46, again to reduce turbulence in exit air flow.Further. and to assist streamlining airflow into and through the airways 38, curved baffles 48 are provided in the throat 20 and its transition to the airways, and other curved baffles 50 are provided about the ends of the divergent panels 42. It will be noted that both sets of baffles have straight parts, those for the lower baffles being in the throat 20 and being adiustably divergent. and those for the upper baffles being above the panel edge terminations 46 and convergent.

In our copending application no. 52139/77 (Serial no. 1602190), pivots 52 for adjustment of the lower baffles 48 allow closure of the throat, i.e. blockage of the airways 38, in order to shut down the ventilator. Although such pivotting lower baffles 48 may still be provided in the illustrated embodiment, the primary and normal means of shutting off the ventilator is to be by pivotting of the upper baffles 50 at 54. Preferably their upper straight parts are moved towards each other so that their ends 56 overlap the divergent panel terminations 46 and their other ends 58 meet the outer casing walls 30, so as to give good weathering protection.

It is also noted that, compared with our copendng application, side wall section is more akin to a goblet shape with the lower parts of the casing walls 30 having a greater curvature to guard against splashing of rain water into the throat. Centre points for the various curvatures are indicated and serve in achieving optimum flow, especially with adjustment of the baffles.

Details are shown of one form of end frame to which the panels constituting walls 30, 34 and the divergent panels of the weathering guard 40 are affixed and the pivots 54 mounted. Specifically, spaced vertical frame members 60 define the throat 20 and help support a horizontal member or beam 62 with diagonal stiffening braces 64 from the mid part of horizontal member 60 and carrying mounting plates 66 for the lower baffles pivots 52. Centrally of the horizontal member or beam 62 is a mount 68 for upwardly divergent supports 70 for the divergent weathering panels 42, and at each end beyond the vertical support members 60, the member or beam 62 is connected at mounts 74 by upwardly convergent struts 72 to the ends of panel supports 70.The mounts 74 are on upwardly divergent frame members 76 extending from adjacent lower casing wall securements 78 on the throat verticals 60 to a top horizontal frame member or beam 86 at the ventilator mouth.

Mounting plates 80 on the members 76 serve both for stiffening braces 84 between them and the top horizontal member 86 and for casing wall location struts 84. The resulting frame has the desired rigidity and the braces 82 carry mounts 88 for the upper baffle pivots 54.

Other satisfactory rigid frame structures may be used, but the provision of a top horizontal member 86 is particularly advantageous in allowing the mounting thereon of linear electric motor means 88 for controlling pivotting of the upper baffles 50 via suitable linkages 90, thereby giving ready access for maintenance purposes via a catwalk 92 (see Figure 3). In order to minimise weight, the elongate carrier for the baffles 50 may be of tubular form, conveniently of square section with appropriate bearings in its mounts and for end intercoupling module-to-module. The number of drive motors required will usually be less than one per module, hence the dashed diagram- matic indication in Figure 1, and is limited by torsional flexing of the baffle carrier.

Normally each drive motor means will serve up to 8 metres or more of baffle carrier to each side, say 2, 3 or 4 modules, and catwalk spacing may correspond thereto.

Referring now specifically to Figure 2, one particular upper baffle drive is shown utilising two linear motors 88A and 88B each mounted to the top member 86 to a different side of its centre and having a linkage to the baffle 50 at the same side in the form of a single arm 94 pivotted to one end to the driven element of the linear motor and at its other end to a bracket on the baffle proper. Both extreme positions of the baffles are indicated in Figure 2.

Although one specific baffle carrier rotation mechanism will be described in relation to Figure 3 for a linear electric motor, it is noted that a rotational motor could be used, say on a depending mount of the top frame member 86 with a convenient rotation reversing linkage associated therewith, or even built into it, and might even be more suitable for a back-up mechanical operating provision than a linear motor.

WHAT WE CLAIM IS:- 1. A natural ventilator in the form of an elongate structure to service at least one building communicating duct or passage along its length, the structure comprising outer longitudinal side walls that initially diverge from adjacent said duct or passage and then converge to upward spaced positions, an inner portion that is spaced above and covers the upper end of the duct or passage, and baffling in airways extending between the inner portion and the side walls with the baffling extending about edges of the inner portion, that baffling being adiustable to close gaps between that inner portion and upper parts of the outer side walls.

2. A natural ventilator according to claim 1, wherein the baffling is curved about said edges.

3. A natural ventilator according to claim 1 or claim 2 wherein the inner portion has sides that are upwardly divergent from a centrally interconnected longitudinal position.

4. A natural ventilator according to any preceding claim, wherein said edges terminate at a level at or near the maximum spacing of the outer side walls.

5. A natural ventilator according to any preceding claim wherein the baffling is pivotted for its adjustment to close said gaps.

6. A natural ventilator according to any preceding claim, comprising a baffle adjustment mechanism to be motor driven.

7. A natural ventilator according to claim 6, comprising a linear electric motor for the baffle adjustment mechanism.

8. A natural ventilator according to claim 7, comprising separate linear motors and linkage mechanisms for baffling in airways to each side of said inner portion.

9. A natural ventilator according to claim 6, 7 or 8, wherein adjustment mechanisms for adjacent modular said structures are intercoupled for driving by the same motor.

10. A natural ventilator according to anyone of claims 5 to 9, comprising baffling maintenance walk-way or platform over the ventilator structure.

11. A natural ventilator having a closure arranged and adapted to operate substantially as herein described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (11)

**WARNING** start of CLMS field may overlap end of DESC **. up to 8 metres or more of baffle carrier to each side, say 2, 3 or 4 modules, and catwalk spacing may correspond thereto. Referring now specifically to Figure 2, one particular upper baffle drive is shown utilising two linear motors 88A and 88B each mounted to the top member 86 to a different side of its centre and having a linkage to the baffle 50 at the same side in the form of a single arm 94 pivotted to one end to the driven element of the linear motor and at its other end to a bracket on the baffle proper. Both extreme positions of the baffles are indicated in Figure 2. Although one specific baffle carrier rotation mechanism will be described in relation to Figure 3 for a linear electric motor, it is noted that a rotational motor could be used, say on a depending mount of the top frame member 86 with a convenient rotation reversing linkage associated therewith, or even built into it, and might even be more suitable for a back-up mechanical operating provision than a linear motor. WHAT WE CLAIM IS:-

1. A natural ventilator in the form of an elongate structure to service at least one building communicating duct or passage along its length, the structure comprising outer longitudinal side walls that initially diverge from adjacent said duct or passage and then converge to upward spaced positions, an inner portion that is spaced above and covers the upper end of the duct or passage, and baffling in airways extending between the inner portion and the side walls with the baffling extending about edges of the inner portion, that baffling being adiustable to close gaps between that inner portion and upper parts of the outer side walls.

2. A natural ventilator according to claim 1, wherein the baffling is curved about said edges.

3. A natural ventilator according to claim 1 or claim 2 wherein the inner portion has sides that are upwardly divergent from a centrally interconnected longitudinal position.

4. A natural ventilator according to any preceding claim, wherein said edges terminate at a level at or near the maximum spacing of the outer side walls.

5. A natural ventilator according to any preceding claim wherein the baffling is pivotted for its adjustment to close said gaps.

6. A natural ventilator according to any preceding claim, comprising a baffle adjustment mechanism to be motor driven.

7. A natural ventilator according to claim 6, comprising a linear electric motor for the baffle adjustment mechanism.

8. A natural ventilator according to claim 7, comprising separate linear motors and linkage mechanisms for baffling in airways to each side of said inner portion.

9. A natural ventilator according to claim 6, 7 or 8, wherein adjustment mechanisms for adjacent modular said structures are intercoupled for driving by the same motor.

10. A natural ventilator according to anyone of claims 5 to 9, comprising baffling maintenance walk-way or platform over the ventilator structure.

11. A natural ventilator having a closure arranged and adapted to operate substantially as herein described with reference to the accompanying drawings.