Abstract:
A pivoted gate across an opening from a gutter into a collector basin. An actuator inside the basin is insensitive to slow flow rates, but includes a rotor with vanes that actuate an opening linkage at sufficiently high rates of flow. A float is included in the actuator to exert a gate-opening torque when the rotor is flooded.

Description:
FIELD OF THE INVENTION 
   Exclusion of debris and trash from gutters and storm drains except during high rates of stream flow, and assured opening of the system under flooded conditions. 
   BACKGROUND OF THE INVENTION 
   Gutters and storm drains are commonly placed alongside roadways to drain casual water and storm water into a collection system leading to treatment plants and then to places of ultimate disposition such as oceans, rivers and spreading grounds. A drain opening when open accepts not only the water but also solid material such as trash and debris which falls or is placed in the roadway. For convenience, this material is collectively referred to as “trash”. 
   During intervals between rains, municipalities and their service organizations generally attempt to collect trash by mechanical means such as sweepers, and to clean out drain basins manually and with vacuums. The purpose is to clear the drainage system to keep it in readiness for the next rain. A persistent problem is that these measures are not always available in time to keep all of the trash in the street. Even sweepers may deflect much of it into the drain. 
   This situation has long been recognized and installations have been made to prevent it. Examples are shown in Martinez U.S. Pat. Nos. 6,217,756, 6,824,677, and 6,869,523. In these devices, a hinged gate is placed in the opening into the drain. At slow rates of flow, water gradually drains, even drips, into the basin through a perforated gate or a gap next to the gate. But the gate remains closed to trash. 
   However, when the flow of water reaches a sufficiently high rate, such as in a storm, an actuator responsive to the stream flow will open the gate and admit the entire flow. This may be accompanied by some trash, but that is inevitable. The drain system is still functional. 
   Known systems to exclude trash in drier modes commonly include an actuator to open a gate which is somehow responsive to the rate of flow of the water. In the U.S. Pat. Nos. 6,217,756 and 6,869,523 Martinez patents, the weight of water in a bucket which leaks or tilts is used as the actuator (or more precisely the sensor). In Martinez U.S. Pat. No. 6,821,053 it is a rotary actuator responsive to the impact force of the stream, an impulse-type reaction. 
   A pervasive problem with systems of these types which must inherently be installed in the basin, is that they are disabled unless they are free for actuation by collecting and retaining a sufficient volume of water for a given period of time, or is available to be directly struck by the entering stream. A “leaky bucket” cannot “leak” when it is totally submerged. A rotor actuated by stream force cannot react to a stream when it is totally submerged. As a result in either case the gate could possibly close at the worst possible time (during very heavy stream flow), resulting in upstream flooding. 
   This problem was recognized in the U.S. Pat. No. 6,821,053 Martinez patent, in which a latch, moved by a float, is intended to hold the gate open when the actuator is flooded. This presents the issue of uncertainty when the “powering system” (the sensor) operates independently of water level-responsive latches. 
   It is an object of this invention, utilizing an impulse-type rotary actuator, to include a secondary opening force into the system exerted by a buoyant float directly connected to the rotary actuator which tends to apply an opening torque to the rotor that will maintain the gate open when the rotary actuator itself is flooded. There results a system that is proof against being disabled by flooding due to excessive flow rates or by plugged-up downstream systems. 
   BRIEF DESCRIPTION OF THE INVENTION 
   The actuator according to this invention is intended to be incorporated into a system which is installed in a drainage basin adjacent to an entry opening from a source of drainage or storm water, like a curb for example. It includes a pivoted gate intended to remain closed when the rate of water flow is suitably slow, and to be opened when the water flow exceeds that rate. A linkage is provided between the actuator and the gate to effect this objective. 
   The actuator itself is a rotor that includes at least one vane. The vane or vanes is or are so disposed and arranged as to be impacted by water which has passed the gate at higher stream rates, but not at slower stream rates. The resulting impulse force (the vane can drain) will cause the rotor to rotate in a first direction to cause the linkage to open the gate and this condition will continue so long as the rate is sufficiently high and the vane is not submerged. When the flow rate decreases sufficiently, the weight of the gate and the linkage will cause the rotor to reverse its direction and the gate will close. 
   This situation can prevail while the rotor remains exposed to the stream. However, if somehow the rotor becomes submerged, this effect is masked. For example if the downstream drainage system is plugged and the basin fills above the rotor, the rotor will not receive an actuating water stream and the gate would close. According to this invention, to prevent this event, a buoyant float is linked to (and preferably is directly attached to) the rotor at the side of the rotor opposite from the vanes, whereby when submerged it will exert on the rotor a torque in the same sense as the stream flow did. Thus there will persist a torque that will maintain the gate open so long as the basin is flooded. 
   This invention contemplates the actuator itself, and also the actuator in combination with the system installed in a basin. 
   The above and other features of this invention will be fully understood from the following detailed description and the accompanying drawings, in which: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side elevation partly in axial cross-section showing the preferred embodiment of the invention in its closed condition, experiencing slow flow; 
       FIG. 2  is a view similar to  FIG. 1  in which the gate starts to open as the consequence of a higher rate of flow; 
       FIG. 3  is a view similar to  FIG. 1  in which the gate is fully opened during rapid flow; 
       FIG. 4  is a perspective view the actuator; and 
       FIG. 5  is a side view of the actuator of  FIG. 4 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   An opening  10  from a gutter is through a curb  11  is shown in  FIG. 1 . It has a bottom sill  13  a top  14  and two sides (not shown) to provide a rectangular aperture leading into a drainage basin  15  into which water drained from the gutter will flow, and will thereafter be passed to a downstream disposal system. A sidewalk  12  or other covering structure is shown, which may be provided with access mean such as a manhole. 
   A frame  20 , includes a pair of U-shaped springy identical and spaced apart rigid metal straps (only strap  21  being shown). Arm  22  engages the underside of the opening. Arm  23  engages the sill. When properly attached, these straps, joined by a transverse plate  24 , will support the system in the basin. 
   A gate  30 , when closed, extends across opening  10 . As preferred it may be perforated, or may have a portion of its periphery spaced from the side or the sides of the opening to form a gap that permits water presented at slow rates to proceed past the closed gate. These dimensions are such as to stop most trash. At slow rates the water  31  merely dribbles down the side wall of the basin, and does not affect the actuator, as will be described. This will attend to periods of light rain, or merely the runoff from lawn watering or car washing. Trash will be retained. 
   As shown in  FIG. 1 , gate  30  is hinged by hinge  32  so it can swing upwardly and inwardly. A linkage  33  is responsive to the rotary position of an actuator  35  pivotally attached to the frame below the level of the sill and spaced from it. 
   The details of the linkage are unimportant and obvious. Any crank type system that transfers torque from a rotor to a hinged gate will suffice. 
   The actuator includes at least one, but preferably two vanes  36 ,  37  spaced from pivot  38 . As shown in  FIG. 4 , each vane has a respective flange  39 ,  40  and open side edges. In the repose condition of  FIG. 1  flange  37  is the closer to the wall of the basin, spaced far enough from that wall so that slow flow  31  will by-pass the actuator completely and the gate will remain closed. Also, assuming that the basin is not plugged up and dry, there will be no reaction with water at all. The inherent bias of the system, starting with the weight of the gate and the linkage is to keep the gate closed. 
   In order to open the gate, a positive torque shown by arrow  45  ( FIG. 2 ) must be exerted. This will start to occur when water flow  46  ( FIG. 2 ) becomes so fast that a stream reaches and impacts the vanes. The impulse of this stream will drive the vanes in the direction of arrow  45 , opening the gate. As the rate increases there will be increased force, fully to open the gate ( FIG. 3 ). This is the subject of Martinez U.S. Pat. No. 6,821,053, which is incorporated herein by reference in its entirety for its showing of such a system. This assumes that the basin is entirely drained at least to a level below the rotor. 
   However, assume now that the rate of flow exceeds the capacity of the downstream opening, or the downstream system is plugged. Then the rotor would be flooded as suggested by wavy line  48 . Without additional features the gate would simply close. 
   To avert this, a buoyant float  50  is attached to the rotor in such a way that when in water its buoyant force will be exerted as a torque in the same rotational sense  49  as the rotor when under impact by the water stream. It is so disposed and arranged that when the rotor vanes are submerged, the float will provide a buoyant force at least equal to that which is lost from the vane or vanes. 
   The float  50  may be as simple as a hollow block  51  of stiff lightweight material or foam fixed to lever arm  52 . It is useful for the block to be supported so as to be rotatable on the arm, thereby better to withstand vigorous hydraulic forces. If preferred, tubes, even hollow tubes, may be used for this purpose. Whatever the situation, its position will be on the opposite side of pivot  38  so its torque will be in the same sense  49  as that of the vane. Clearly its weight should be such that it does not appreciably adversely resist the torque applied by the water stream. 
     FIGS. 1–3  illustrate normal operations with the water level in the basin (if any), below the rotor. In  FIG. 3 , line  48  represents a flooded level of water in the basin. Notice that the system will have remained open. The vanes are useless, but the submerged float exerts a torque to hold the system open by reason of its buoyancy. 
   This invention thereby provides a system to hold a drain system opening in its closed position at slow and no flow, and to open the system at high rates of flow, and to keep it open even if the system itself becomes flooded. 
   This invention is not to be limited by the embodiment shown in the drawings and described in the description, which is given by way of example and not of limitation, but only in accordance with the scope of the appended claims.