A TIGHT CLOSING DAMPER

Abstract: A tight closing damper, preferably in the shape of a Venetian shutter with lids (5, 6). Arms (3, 4) carrying the lids (5, 6) are designed to permit opening of the damper by turning a shaft (1) at least close to 90<o>, which shaft is journalled on one side of the damper wall and on which the arms (3, 4) are secured in such a manner that the gas may flow freely through the openings.

Description: A tight closing damper In the ventilation field there are often used dampers of the so called Venetian shutter type to open or shut off an air passage, and also for control of the air flow therethrough. When the commercially available dampers of the Venetian shutter type are closed there still exists a certain leakage of air or gas, which leakage may amount to one or a few per cent of the nominal flow. In most cases such a leakage may be neglected, but in some applications it is a definite desire to have entirely tight dampers. The present inventions aims at providing a damper which meets the just mentioned demand in a simple and appropriate way. To the just mentioned end the damper according to the invention has been designed so, as is defined in principle in the characterizing clause of claim 1. Pig. 1 is a side view, partly in section, of one embodiment of a damper according to the invention. Fig. 2 shows the damper in Fig.l in an end view and into a slightly reduced scale. Fig. 3 illustrates a modification of the damper in Fig.l; Fig. 4 and 5 illustrate, in cross-section, two different embodiments of sealing means. According to Fig.l the damper shaft 1 has been disposed at some distance a from the damper wall 2, which remedies the need for air-tight journals for the shaft 1 as well as for the arms 3 and 4, which carry the closing lids 5 and 6. The disposition of the shaft 1 on one side of the damper wall has been made possible in that the arm 4 has been shaped in such a manner that it passes freely through the air passage 8 also when the lids 5 and 6 have been opened fully, close to 90°, by a turning of the shaft 1, to which the arms 3 and 4 are secured. The lids 5 and 6 seal off under an even pressure against elastic gaskets 9 and 10 through pivoting and resilient mountings 11 and 12 on the arms 3 and 4. If the lids are short one mounting per lid is enough. If the lids are longer the tighty closing effect will be the same if 1 each lid is supported by two or more mountings, with the corresponding arms secured to the shafts 1, Fig.2. Fig.2 illustrates, in end view, the design of a second Venetian shutter type embodiment of the damper. It will be noted that a reduction of the total flow area arises due to the cross-beams 14 with gaskets, but this is the price one has to pay in order to achieve the improved sealing. The shafts 1 in Fig.2 are journalled in bearings 16 and are controlled by means of arms and links in the way which is common with Venetian shutter type dampers. The resilient mountings 11 and 12 for the lids on the arms, Fig.l, may be accomplished by means of spiral springs or other types of resilient components, such as rubber pads etc. If the distance a in Fig.3 is comparatively great in relation to the distance b_ between the air flow passages then the abutment of each lid against its gasket 9 may take place under a comparatively great angle v., which may cause a less satisfying sealing and a substantial wear on the gasket. By designing the arm 4 in such a manner that the lid in unloaded condition does not hit the uppermost and lowermost edges of the gasket 9 simultaneously but instead with some inclination v,, the lid will then, as it is pulled against the gasket by the privotal and resilient mounting, hit the gasket under an angle v~ from a normal to the gasket, i.e. close to perpendicularly to the gasket, and, thus, the problem of the too oblique engagement is eliminated. The distance a of the shaft from the damper wall. Fig.3, may vary and may go down to 0 if the damper wall bulges slightly outwardly, which also eliminates the problem of the too oblique engagement with the gasket, but, of course, complicates the manufacture. The construction is not limited to a design wherein the lids are coupled together in pairs but can also function with one lid only on each shaft. If it is a question of hot gases, e.g. hot flue gases, the gasket may be designed so as illustrated in Fig.4, i.e. as a gasket member of a braided or woven strand of ceramic fibers, which are available for temperatures even up to 1000° C. Due to the pivotal mounting an even pressure all away round the edge of the lid is achieved also at these high temperatures. The resilient component should be disposed outside the hot space at elevated temperatures, if the temperature is so high that metallic springs do not maintain their resiliency. If this would be the case then one would have to work with a privotal mounting only of the damper lid or lids.

Claims: Claims 1. A tight closing damper comprising individual lids (5,6) or groups of such lids, preferably arranged as Venetian shutter type lids, wherein a journal mechanism for the lids is affixed to a damper wall (2) with openings (7,8) for passage of the gas, around which openings there are disposed elastic gaskets (9,10) to form continous, gastight seals, characterized in that arms (3,4) which support the lids (5,6) are designed in such a manner that they permit opening of the damper by an at least 90 turning of a shaft (1) , which is journalled on one side of the damper wall and on which the arms (3,4) are affixed so that the gas can flow freely through the openings. 2. A damper as claimed in claim 1, characterized in that the lids (5,6) are pivotally and resiliently secured to the arms (3,4) in such a manner that they are permitted to abut their gaskets with an evenly distributed pressure. 3. A damper as claimed in claim 1 or 2, characterized in that the lids (5,6) are affixed to their arms with at least some inclination so that, on closing the damper, one edge of the lid abuts its gasket portion in advance of the opposite edge of the lid hits its gasket portion (Fig.3) .

Inventors: STENFORS ERIK, STENFORS, ERIK
Applicants: REGENAIR AB
Application year: 1984
Main classification: F24F13
IPC codes: E04B1, F15D1, F24F13