EP0472569B1

EP0472569B1 - A damper

Info

Publication number: EP0472569B1
Application number: EP90907081A
Authority: EP
Inventors: Taisto Tetri
Original assignee: Lapinleimu Oy
Current assignee: Lapinleimu Oy
Priority date: 1989-05-15
Filing date: 1990-05-09
Publication date: 1995-02-01
Anticipated expiration: 2010-05-09
Also published as: AU5561090A; WO1990014564A1; FI88961B; NO175954B; EP0472569A1; FI892328L; NO914460D0; NO914460L; DE69016654D1; FI892328A0; NO175954C

Abstract

The invention relates to a damper intended to be used for regulating the flow or air or other gases. The damper generally comprises a plurality of laths (3) journalled in a frame (2). The object is to provide a novel damper the ends of the laths (3) of which are placed tightly against the frame forming a passage for the flow of gas. This is achieved by providing the ends of the laths (3) with a flexible seal member (6, 7) following closely the frame.

Description

The invention relates to a damper according to the preamble of claim 1 and comprising at least one lath journalled in a frame. The damper generally comprises a plurality of laths.
Dampers are used widely for regulating and/or closing the flow of air and various gases.
The ends of the laths should be in close contact with the frame forming a passage for the flow of gas, without causing excessive friction. So far this problem has not been solved satisfactorily.
In prior art solutions, the ends of the laths are fixed and inflexible, and a sealing material is fastened either to the end of the lath or to the frame. The soft sealing material, generally felt or silicone rubber, rubs against the steel of the frame during the regulating movement. The soft material has a high friction resistance when sliding along the steel, whereby the seal wears out rapidly and may be torn completely. A severe risk is caused by the frosting of the seal in the wintertime, which may locally freeze up the seal to the frame. When the motor of the damper opens the damper, the seal may be locally torn completely. The damaged seal causes undesired leakage. As a result, the energy and/or maintenance cost is increased considerably.
Due to the high friction resistance, a high torque is required to turn the damper, that is, a large and expensive servomotor.
The situation is made even worse by the manufacturing inaccuracies occurring frequently in the frame and/or the laths, and even minor faults in installation may deform the frame, thus increasing clearances and the amount of leakage and friction. Due to faults in installation, the frame may remain in an oblique position or it may be bent. Deformations may occur also in normal use. These problems are further aggravated in solutions in which the seal between the frame and the lath ends is formed by a flexible steel strip.
A damper according to the preamble of claim 1 is known from US-A-41 92 098. This prior art document discloses a multible blade air damper having individual end edge seal elements for sealing of the end edges to the frame in the closed position. The seal elements are mounted in end-to-end relation and define a continuous flat sealing surface in opposed, abutting alignment with the individual flat planar end edges of the plates. Each seal element is a thin spring-like resilient metal plate and is compressed between the end of an aligned blade and the damper frame.
It is the object of the present invention to provide a damper which aviods the above-mentioned drawbacks and is thus less susceptible to wear and reduces the torque required to turn a damper.
This object is solved according to the present invention by a damper including the features of claim 1.
Preferred embodiments of the invention are defined in the dependent claims.
In the damper of the invention, the ends of the laths are not fixed nor inflexible; instead, they are able to follow possible deformations in the frame. The lath ends are "floating" and always in close contact with the frame.
In the following the invention will be described in greater detail with reference to the examplifying embodiments shown in the attached drawings.
Figure 1 is a schematic front view of a damper.
Figures 2 to 6 are sectional views through alternative embodiments along the line A-A shown in Figure 1.
The damper is generally designated with the reference numeral 1, the frame with the reference numeral 2, and a lash with the reference numeral 3. The laths 3 are preferably insulated. The laths 3 are turned by means of a lever mechanism, for instance. The lever mechanism may be known per se and is therefore drawn merely in outline in Figure 1, the reference numeral 4.
According to the invention, the lath end is flexible, that is, floating in such a way that it follows closely and lightly the frame 2 irrespective of minor deformations of the frame. Figures 2 to 6 show alternative constructions for a flexible lath end.
In the embodiment of Figure 2, a platelike, flexible seal 6 is attached to the end of an insulated lath 3, and a "floating" cover piece 7 to be placed in contact with the frame 2 is positioned on the seal 6. The cover piece 7 is preferably made of metal or of wear-resistant, lubric plastic, whereby the friction remains low and a long service life is obtained while the sealing effect remains unimpaired.
In Figure 3, a flexible tongue 9 bearing against the end of an insulated lath is attached to a floating cover piece 8, and the branches 8a of the cover piece 8 are in close sliding contact, the reference numeral 10, with the side surfaces of the lath 3.
In Figure 4, a flexible tubular seal 11 of rubber or plastic, for instance, is attached to a cover piece 12.
In Figure 6, a spiral spring 15 is provided between a cover piece 16 and the end of an insulated lath 3, seals 14 being fitted between the branches 16a of the cover piece and the side surfaces of the lath 3.
The spiral spring 15 is not absolutely necessary; the seals 14 between the branches 16a of the cover piece and the side surfaces of the lath may alone provide the required flexibility.
Figure 5 shows an embodiment in which no separate floating cover piece is provided. A tubular seal 13 is provided between the end of an insulated lath 3 and the frame 2. In the tubular seal 13 a surface 13a to be placed in contact with the frame 2 is wear-resistant and lubric. Preferably, the seal 13, or at least its portion to be pressed against the frame 2, is made of a material of high mechanical strength to prevent damage to the seal at subzero temperatures.
In Figures 2 to 6, the reference numeral 5 designates a journal on which the lath 3 is mounted to the frame 2. Clearances shown in the drawing between the cover pieces 7, 8, 12 and 16 and the frame 2, respectively, are not real; in the drawing, they make it easier to distinguish the different parts from each other. The situation is the same in the case of the flexible tongue 9 and the tubular seals 11 and 13.
To decrease friction and to improve strength, the frame 2 is preferably provided with an elevation 17 extending in parallel with the lath when the lath is in the closed position.
In the embodiments of the drawing, the flexible seal member is in each case attached to the end of the lath 3, whereby the frame 2, preferably only the elevation 17 of the frame, acts as a counter surface for the seal member.

Claims

A damper comprising at least one lath (3) journalled in a frame (2), whereby a flexible seal member (13; 6, 7; 8, 9, 10; 11, 12; 14, 15, 16) is mounted between at least one end of the lath (3) and the frame (2) characterized in that the seal member is floatingly mounted on the end of the lath (3) to closely follow the frame (2) flexibly in the longitudinal direction of the lath, whereby the frame (2) forms a fixed counter surface for the seal member.
A damper according to claim 1, characterized in that the flexible seal member (13) or its counter surface is made of a material forming a wear-resistance and lubric surface (13a) to be placed in contact with the frame (2).
A damper according to claim 1 or 2, characterized in that in the seal member (13) the portion to be placed in contact with the frame is made of a material of high mechanical strength.
A damper according to claim 1, characterized in that the flexible seal member comprises a flexible seal (6; 11; 14) and a cover piece (7; 12; 16) to be placed in contact with the frame (2), the cover piece being attached to the seal so as to surround it substantially on all sides.
A damper according to claim 4, characterized in that the seal is a platelike part (6) made of a flexible sealing material.
A damper according to claim 4, characterized in that the seal is a tubular seal (11) made of a flexible material.
A damper according to claim 4, characterized in that the cover piece (16) comprises branches (16a) extending in parallel with the side surfaces of the lath (3), seals (14) being provided between said branches (16a) and the side surfaces of the lath (3).
A damper according to claim 3, characterized in that a spiral spring (15) is provided between the end of the lath (3) and the cover piece (16).
A damper according to claim 4, characterized in that the cover piece comprises branches (8a) having sealing surfaces (10) to be pressed against the side surfaces of the lath (3), a flexible tongue attached to the cover piece (8) being provided between the end of the lath and said cover piece.