1. Technical Field
This invention relates to dampers, and more particularly, to mechanisms for operating various
usage dampers.
2. Background
In the prior art, a multi-blade damper was positioned in an air duct. The damper could have been for fire, smoke or other air control. The damper was opened by a linkage mechanism attached to, for example, a cable, such that when the cable was pulled, the damper operated (i.e. opened).
To aid in getting the damper to operate, a motor driven fan is used upstream (or downstream) of the damper. A motorized damper operator is used for center pivoted blade dampers and for off-center pivoted blades. It is used to supply air flow in the heating, ventilating and air conditioning system. This motor operator required electrical circuitry not only to operate the center pivoted damper, but more particularly, to operate the damper synchronously with the start-up of the air flow in the air duct. If, for example, the air supply fan came on and the damper didn't open promptly, the duct could be blown apart.
In accordance with my invention, the air conditioning fan itself provides the force means to operate the damper without the need for the separate motor and circuitry.
Furthermore, in cases where the fan does not provide enough air flow power to begin the opening of the damper, it is desirable to provide a means to enhance the airflow initiating means sufficiently to start air flow to operate the damper.
In a system having a duct, an air supply means to supply air flow in said duct and a damper means operable between an opened and a closed position, positioned downstream in said air flow, I have invented a windmill operator means connected to said damper means responsive to air flow in said duct to open said damper means.
In accordance with the preferred embodiment of my invention, a system having a duct, an air supply means to supply air flow in said duct and a damper means operable between an opened and a closed position, positioned downstream in said air flow is provided with a windmill operator means connected to said damper means responsive to air flow in said duct to open said damper means. A small windmill 40 is mounted upstream of a damper 49 in the air handling duct 41 (
In one embodiment, the windmill 40
When air goes into the duct 41 and the damper 49 is closed, the pressure builds up within the duct, eventually forcing the access door 42 to open. Once the access door 42 opens, the windmill 40 starts to turn; because air is flowing through the duct and out the resulting opening 45 in the duct wall 43. Prior to that time, there is no real air flow; but rather just a build-up of pressure.
The windmill operator means further comprises a windmill means and a damper operator means connected to said damper means, comprising a cable connected at one end thereof to said damper means and at the other end thereof to a force transmission means connected to said windmill means.
Mounted to this windmill is a small gear box 44 (
This causes the pressure to drop in the air duct. A spring 47 (
Once the damper is fully open and against its built-in stops (not shown, but well known in the art), the windmill simply stalls out and stops spinning; because it cannot overcome the damper stop force. Even though the windmill stops turning, it still provides a force to hold the damper open.
When the fan 50 is turned off, the windmill loses its power and the damper is closed, such as, for example, by a spring (not shown, but well known in the art). My drive mechanism then re-arms itself to again open the damper when the fan comes back on.
There is a particular advantage to this device with fire and smoke dampers, because such dampers are normally operated by means of electrical controls and motors. This damper opening mechanism eliminates all the electrical motors, controls and wiring and provide power off closure fail safe operation; except when the windmill is a partial power assist to an otherwise inadequate operator. It takes very little for an initial opening of the damper to provide sufficient air flow to start the windmill. I have determined that small, highly geared windmill motor blades are nearly invisible to the air flow; and will fully open the damper. An electric or pneumatic motor imposes about the same (small) air flow resistence as the wind mill.
Furthermore, the windmill can be used to supply electric or pneumatic power to a battery or air tank, respectively.
Also, it can be used for positive blade positioning to use dampers with adjustable stop and springs or weight to set up space pressurization in order to establish space to space pressure differentiation.
In another embodiment I provide a force transmission means and a disengagement means utilizing a heat responsive bimetallic mechanism means. These are shown in
The shaft 60 has a spline gear 62 at its end; which engages a gear in the gear train 64 (having a plurality of gears) in the gear box 44 (
The shaft 70 (
The gear train 64 is a reduction gear train of most preferably in the range of 300 to 600 to one; to give the windmill a large mechanical advantage.
The force transmission means further comprises a run-away prevention means to prevent the windmill from free-wheeling when the windmill shaft is disconnected from the gear, comprising a first member fixed with respect to rotation of said shaft and a second member connected to the windmill shaft and positioned so as to engage the first member and thereby interfere with rotation of the windmill shaft. The first member comprises a pin 122 which extends downwardly from the outer bearing 67 through the frame 66.
A collar 65 is fixed to the shaft 60 (
To raise the shaft 60, I provide the following means. The shaft 60 is relieved at 61. A bimetallic member 100 has a yoke at its free end providing an opening designated generally 63; so that its free end can embrace the shaft in the relieved portion 61 (
The heating of the bi-metallic element can also be accomplished by electrically heating a heating element 102 that is vulcanized onto the bimetallic member. Heat is provided through an electrical heat application means comprising a micro switch 104, wires 106 and contacts 114. This heating moves the shaft out of engagement with the gear train.
The application of heat can be terminated by an automatic termination means, comprising the micro switch 104, which can be deactivated by an arm 108 and contact 110 to disconnect the application of heat and prevent the heating element from burning up.
The pins 122 and 124 provide a run-a-way prevention means to prevent the windmill from free wheeling in the “hot” raised position.
When the heating of the bimetallic element stops and it cools down, it drives the shaft 60 down in the direction of the arrow “C” and thereby, re-engages the spline gear 62 with the gear train 64.
To provide a greater mechanical advantage for the lifting action of the bimetallic element in raising the shaft, I have provided a mechanical enhancing means comprising a lever 90 pivotally mounted to a mullion 91. The free end of the lever is positioned to lie over the free end of the bi-metal element 100. A groove in the lever, embraces the shaft 60 in the relieved portion 61. When the bi-metal is heated, it rises its free end and, thereby, raises the lever 90 and the shaft 60.
It will be understood by those of ordinary skill in the art that the air flow to operate the damper may be provided in a separate small air flow ducting means positioned between the damper and a fan or parallel with the damper.
In another embodiment, a butterfly or other air flow responsive damper, such as a back draft damper is used. The back draft type damper 149 (
Another version positions the windmill gear box arrangement of the first embodiment outside the air duct, in a duct of its own, which is vented, so that when the air flow comes on, the air passes through the smaller duct; turns the windmill; and then the windmill opens the damper. This conduiting of a small separate air flow can be independent of the dampered positive or negative air flow source.
A very small, low power damper start-up motor may be used.
If a pulley is used as the take-up means, in stead of a drive arm 46, the gear train reduces the turning of the pulley to approximately one RPM.
This application is a continuation-in-part of my prior provisional application No. 60/585,990 filed Jul. 7, 2004 entitled WINDMILL DAMPER OPERATOR, the disclosure of which is incorporated herein by reference as if fully set forth.
Number | Name | Date | Kind |
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3806733 | Haanen | Apr 1974 | A |
3815638 | Martin | Jun 1974 | A |
4311435 | Bergero | Jan 1982 | A |
4446418 | Richardson | May 1984 | A |
4501389 | Kolt | Feb 1985 | A |
4527072 | van Degeer | Jul 1985 | A |
5117143 | Iddings | May 1992 | A |
Number | Date | Country |
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55014941 | Feb 1980 | JP |
01127846 | May 1989 | JP |
Number | Date | Country | |
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20060006245 A1 | Jan 2006 | US |
Number | Date | Country | |
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60585990 | Jul 2004 | US |