A VENT DAMPER

Abstract: A damper plate (2) for controlling a venting aperture includes a member (4) which at varying humidity shows a tendency to buckle and straighten out, thereby changing the free passage area of the aperture.

Description: A Vent Damper This invention relates to a vent damper for automatically regulating an airing aperture in dependence of varying condition of air humidity, particularly for the purpose of maintaining a desired degree of humidity 5 in a room. To control such vent dampers it is known to make use of one or more humidity sensors that are suitably located in the room and which for instance electrically activate a servomotor to move the damper 10 in dependence of variations in the degree of air humidi¬ ty. A simpler and thus cheaper solution which, moreover, does not require particular supply of energy to move the damper is known from German patent No. 15 717.397 relating to air moistening in a room heated by combustion of gas in a furnace. The water vapour con¬ tained in the combustion products is used for the moist¬ ening, and in this respect the outlet pipe of the furnace has an opening or port controlled b " a damper which 20 dependent on its position directs more or less of the combustion products, and thereby more or less of the moist steam, out from the pipe so as to be mixed with the air in the room. According to the patent the damper is automatically adjusted in dependence on the humidity 25 content of the air which is sensed by a diaphragm fixed in a frame. The deflection of the diaphragm relative to the frame increases by increasing moisture and the diaphragm is mechanically connected with the camper, ' thereby causing this damper to be moved in the opening 30 and closing direction due to decreasing and increasing diaphragm deflection, respectively. A similar arrangement is likely to be used straight away in connection.with a damper that controls a venting aperture or port from a room, and instead of 35 the diaphragm another humidity sensitive member may be used, for instance a block of hygroscopic wood as is known from various air moistening devices. Relevant examples are known from US patents Nos. 976,150, 1, ' 718,389 and 1,755,276. The purpose of the invention is to provide for a further simplification of automatically operating vent dampers of the type specified above, and this is obtained by the fact that the damper in itself includes a sheet or plate shaped member which by varying hu idi- ty content tends to buckle and straighten out, the damper being positioned so in relation to the aperture that, as a consequence of said tendency, it increases and decreases the through-flow area by increasing and decreasing humidity content. Accordingly, the adjusting mechanism reacting on the degree of humidity is thus constituted so to say by the very damper, ' thereby eliminating the need of some transmission from a separate humidity sensor to the damper. This entails considerable savings in mater- ials and wages both in the production stage and when installing the damper at the place of application. : The damper plate may appropriately in a manner known per se, cf. US " patent No. 976,150, be a laminate comprising a humidity sensitive material, suitably a wood veneer, and a relatively humidity insensitive reinforcing sheet. This sheet may not only improve the mechanical strength of the damper but it may also cause it to be preloaded to a certain degree against its closing position. Moreover, the humidity sensitive material may by heat insulation be protected against vapour condensation. In this way it may be ensured that the humidity content of the material under all circumstances comply with the state of humidity of the air in the room. An embodiment of the vent damper according to the invention will now be more fully explained with 'SURE OMPI reference to the drawing, in which Fig. 1 illustrates the damper, viewed from the inside (the side towards the room) and in an open posi¬ tion, and 5 Fig. 2 is a section on a larger scale along line II-II in Fig. 1. Fig. 1 illustrates a rectangular frame 1 adapted to be installed in a venting or airing aperture in a wall, not shown, while 2 is a damper plate which at its 10 upper edge is hingedly suspended in the frame and at its lower edge may be provided with lateral pins 3 which are displaceable in guiding grooves in the lateral pieces of the frame. The damper 2 consists mainly in a thin wooden 15 sheet 4 that is plane when dry. The surface of said wooden sheet facing the air in the room is uncovered while its opposite side is covered ' by a heat insulation 5, a reinforcing or foil sheet, such as a thin metal sheet 6, Fig. 1, being appropriately inserted between 20 the two layers 4 and 5. The bare side of the wooden sheet may possibly be provided with milled groves for increasing the area of the surface so that it particularly quickly reacts on variations in the " humidity content of the air in the room. Another pos- 25 sibility of accelerating the reaction of the wooden sheet consists in subjecting it to a chemical treatment in order to washing out lignin and other substances retarding the absorbing of and giving off humidity. In the illustrated situation the degree of humid- •* , 30 ity is supposed to be relatively high so that venting "=' is needed. Also the wooden sheet 4 is therefore humidi¬ fied and has thus assumed the illustrated curved or buckled shape entailing that the damper lets part of the venting aperture be uncovered. At decreasing degree of 35 humidity the damper approaches its plane state, thereby causing complete blockage of the aperture. An inverted arrangement is also imaginable, i.e. OMPI - using a humidity sensing member, such as a wooden sheet which due to humidifying changes its shape from plane to curved state or from less curved to more curved shape. _ OΛtPI

Claims: PATENT CLAIMS 1. A vent damper for automatically regulating an airing aperture in dependence of varying condition of air humidity,, particularly for the purpose of main- 5 taining a desired degree of humidity in a room, characterized in that the damper (2) in itself includes a sheet or plate shaped member (4) which by varying humidity content tends to buckle and straighten out, the damper being positioned so in relation to the aperture ■ 10 that, as a consequence of said tendency, it increases and decreases the through-flow area by increasing and decreasing humidity content. 2. A vent damper as claimed in claim 1, characterized in that the damper plate is a laminate 15 of a humidity sensitive material (4), appropriately a- wood veneer, and a relatively humidity insensitive reinforcing sheet (6) . 3. A vent damper as claimed in claim 2, characterized in that the humidity sensitive material 20 (4) by heat insulation (5) is protected against vapour condensation. OMPI

Inventors: SVANE PETER, SVANE, PETER
Applicants: RASMUSSEN HOLDING AS V KANN, V. KANN RASMUSSEN HOLDING A/S
Application year: 1983
Main classification: F24F13
IPC codes: F24F13