Patent Publication Number: US-9885190-B1

Title: Safety system for controlling fluid flow into a suction line

Description:
This is a continuation of application Ser. No. 13/796,693, filed Mar. 12, 2013. 
    
    
     ORIGIN OF THE INVENTION 
     The invention was made by employees of the United States Government and may be manufactured and used by or for the Government for governmental purposes without the payment of any royalties. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to safety systems for use with fluid suction lines. More specifically, the invention is a safety system that couples to the inlet of a fluid suction line and controls the flow of fluid therethrough in order to prevent injuries when there is human interaction with the safety system. 
     2. Description of the Related Art 
     Any large fluid-filled tank (e.g., pool, spa, mixing tank, storage tank, etc.) typically has at least one drain formed therein. Frequently, a suction line is coupled to the drain to facilitate removal of fluid from the tank. For example, pools and spas use pumps to continuously pull water through a drain and suction line as part of the water filtration process. 
     A problem with pool/spa drains (or any other tank drain that would encounter human interaction) is that human hair or extremities can become entrapped in a drain or suction line. Forces at these drains can be as much as several thousands of pounds. At these levels, human hair, fingers, toes, etc. can be violently sucked into the drain/suction line such that a person cannot free themselves from the drain/suction line. In the case of long hair, knots in the hair can readily form behind the drain as the turbulent flow of water moves through the drain and into the suction line. In the case of fingers, toes, etc., the violent sucking of the extremity can cause immediate injury thereto. If the case of suction force confined to a small area (e.g., the connection point for a pool&#39;s vacuum line), a person&#39;s torso could provide a sufficient seal to the suction area thereby trapping the person thereat. Further, if such trapping occurs well under the water&#39;s surface, a person could be in danger of drowning. Still further, in extreme cases, intestinal disembowelment could occur if a person&#39;s rectal area were trapped over a drain/suction line. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a safety system that can control the flow of a fluid into a suction line in order to prevent human entrapment conditions. 
     Another object of the present invention is to provide a safety system for coupling to the inlet of a tank, pool or spa&#39;s suction line. 
     Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings. 
     In accordance with the present invention, a safety system is provided for placement at the inlet of a pool&#39;s suction line in order to control water flowing from the pool into the suction line. The safety system includes a sleeve adapted to fit within the pool&#39;s suction line at the suction line&#39;s inlet. The sleeve is open at a first end thereof that is approximately aligned with the suction line&#39;s inlet. The sleeve terminates at a second end thereof with a plate that resides within the suction line. The plate has a plurality of holes formed therethrough. A housing defining a plurality of distinct channels therein is fitted in the sleeve so that the distinct channels lie within the sleeve. Each of the distinct channels has a first opening on one end thereof and a second opening on another end thereof. As a result, a plurality of first openings and a plurality of second openings are defined. Each of the second openings resides in the sleeve. Each of the distinct channels is at least approximately three feet in length. Each of the first openings is in fluid communication with the water in the pool. The first openings are distributed around a periphery of an area of the housing that prevents coverage of all the first openings when a human interacts therewith. A first pressure sensor is coupled to the sleeve to sense pressure therein, and a second pressure sensor is coupled to the plate to sense pressure in one of the plates&#39; holes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING(S) 
       Other objects, features and advantages of the present invention will become apparent upon reference to the following description of the preferred embodiments and to the drawings, wherein corresponding reference characters indicate corresponding parts throughout the several views of the drawings and wherein: 
         FIG. 1  is part schematic view and part cross-sectional view of a safety system used to couple a volume of liquid to a suction line in accordance with an embodiment of the present invention; 
         FIG. 2  is a cross-sectional view of a safety system for incorporation into a new pool construction in accordance with an embodiment of the present invention; 
         FIG. 3  is a cross-sectional view of a safety system for incorporation into a new pool construction in accordance with another embodiment of the present invention; 
         FIG. 4  is a plan view of the top of a retro-fit safety system for use with an existing pool in accordance with an embodiment of the present invention; 
         FIG. 5  is a cross-sectional view of a retro-fit safety system using the top illustrated in  FIG. 4  with a top surface thereof that presents topographic features in accordance with an embodiment of the present invention; 
         FIG. 6  is a plan view of the top of a retrofit safety system for use with an existing pool in accordance with another embodiment of the present invention; 
         FIG. 7  is a cross-sectional view of a retro-fit safety system using the top illustrated in  FIG. 6 ; 
         FIG. 8  is an isolated perspective view of a safety system housing for use with an existing pool in accordance with another embodiment of the present invention; 
         FIG. 9  is a side view of a safety system incorporating the housing illustrated in  FIG. 8  with the safety system installed in the inlet of a pool&#39;s suction line; 
         FIG. 10A  is a plan view of the top of a multiple piece safety system housing in accordance with another embodiment of the present invention; 
         FIG. 10B  is a cross-sectional view of the multiple piece safety system housing illustrated in  FIG. 10A ; 
         FIG. 11  is a cross-sectional view of multiple piece safety system housing in accordance with another embodiment of the present invention; and 
         FIG. 12  is an isolated schematic view of a flow sleeve instrumented with pressure sensors in accordance with an embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     Referring now to the drawings and more particularly to  FIG. 1 , a safety system for controlling the flow of fluid (e.g., water) from a relatively open region  100  to the confines of a suction line  200  is shown and is referenced generally by numeral  10 . Typically, a vacuum force in the direction of arrow F is applied to system  10 . System  10  controls the flow of fluid (not shown) from region  100  into suction line  200  in a manner that prevents human entrapment or entanglement with system  10  even when force F is on the order of several thousand pounds. Open region  100  is representative of a tank/pool/reservoir holding a fluid that must be drawn into suction line  200 . It is assumed that there is potential for human interaction with suction line  200 , accidental or otherwise, thereby requiring the need for system  10 . By way of illustrative example, region  100  is assumed to be a pool or spa filled with water such that suction line  200  represents a drain or skimmer line thereof used to continuously cycle water from region  100  into and through suction line  200  by means of a pump (not shown). 
     The basic principles embodied by the present invention will be explained using system  10 . In general, system  10  defines a plurality of distinct closed conduits/channels  12  that lead from region  100  to suction line  200 . Each of channels  12  has a first open end  12 A in fluid communication with region  100  and a second open end  12 B in communication with suction line  200 . Each of closed channels  12  is long enough (e.g., typically approximately 3 feet or more in length from open end  12 A to open end  12 B) such that long thin objects (e.g., hair, bathing suit straps, bathing suit drawstrings, etc.) drawn into two or more separate opens ends  12 A and corresponding channels  12  cannot be joined and entangled at corresponding open ends  12 B in suction line  200 . 
     Open ends  12 A are distributed about/around an area defined by dashed lines  20 . For clarity of illustration, only four of closed channels  12  are illustrated. Note that while area  20  is depicted to be rectangular, the present invention is not so limited as area  20  could be any regular or irregular geometric shape without departing from the scope of the present invention. Likewise, while closed channels  12  are depicted as linear, the present invention is not so limited as closed channels  12  could be non-linear, helical, or otherwise complexly curved along their lengths to thereby define longer paths in a smaller area. 
     The goal/function of area  20  is to define a region that positions open ends  12 A in a geometrical arrangement that prohibits coverage of all or most of open ends  12 A when there is some form of human interaction with system  10  from region  100 . More specifically, area  20  and arrangement of open ends  12 A are such that various human extremities (e.g., hair, fingers, hands, toes, feet, etc.) and larger body parts (e.g., rectal areas, torso regions to include one&#39;s stomach or back, etc.) cannot cover a substantial number or all of open ends  12 A. 
     System  10  can also include a secondary device  14  having multiple pass-through holes  14 A extending therethrough. Device  14  is typically a multiple-hole plate, pipe or plug placed between open end  12 B and spanning a portion  200 A of suction line  200  leading away from system  10 . Plate/plug  14  eliminates limb entrapment in suction line portion  200 A if system  10  becomes damaged or is missing. 
     A variety of constructions embodying the principles of system  10  are possible without departing from the scope of the present invention. As will be explained further below, some of the constructions are designed for a new pool/spa/tank constructions, while others are retro-fit designs readily installed in existing construction. 
     Referring first to  FIGS. 2 and 3 , two embodiments of the present invention for new pool constructions will be presented/explained. In  FIG. 2 , a portion of the bottom of a pool is indicated by reference numeral  300 . A portion  300 A of bottom  300  incorporates topographic features such as a wavy or undulating surface as illustrated. Formed in the bed  302  of pool bottom  300  are closed channels  12  with open ends  12 A located in undulating surface region  300 A and open end  12 B located in suction line  200 . Since undulating surface region  300 A is a non-flat surface, there is little to no possibility that a human body part will be able to cover undulating surface region  300 A and open ends  12 A. Further, the length of each closed channel  12  is typically at least approximately three feet in length. In this embodiment, closed channels  12  are linear along their lengths leading to suction line  200 . Plate/plug  14  can be included as described above. 
     In  FIG. 3 , closed channels  12  are similarly formed in pool bed  302  but are nonlinear along their lengths. For example, channels  12  could be helical or otherwise complexly curved along their lengths to thereby define longer path lengths in a smaller area. Similar to the previous embodiment, each closed channel  12  is typically at least approximately 3 feet long with open ends  12 B positioned in suction line  200 . Plate/plug  14  can be included as described above. 
     The present invention can also be realized in a variety of kit-type constructions designed to be retrofit to existing pool-to-suction line interfaces. Several non-limiting examples will be disclosed herein with the aid of  FIGS. 4-11 . In each of the embodiments, a pool&#39;s suction line is referenced by numeral  200 , the pool bottom is referenced by numeral  300 , and the pool water to be pulled into suction line  200  is referenced by numeral  102 . In each of the ensuing retrofit designs, the basic principles detailed above will be followed. 
       FIGS. 4 and 5  illustrate top and cross-sectional views, respectively, of a safety system  50  having a flow housing  52  and a flow sleeve  54 . A top plan view of housing  52  is shown in  FIG. 4 . In general, sleeve  54  fits within suction line  200  at the inlet of the suction line and housing  52  fits within sleeve  54 . For ease of installation, sleeve  54  can include an annular flange  54 A (e.g., integrated with sleeve  54 ). In this way, sleeve  54  can simply be dropped into suction line  200  so that the open end of sleeve  54  defined at flange  54 A is aligned approximately with the inlet of suction line  200  as shown. Flange  54 A can be cemented or otherwise adhered to the inlet of suction line  200  if desired. 
     Housing  52  has a top area  52 A thereof exposed to pool water  102 . Housing  52  is generally T-shaped and defines/supports a number of closed channels  12  (each of which is typically at least 3 feet in length) with open ends  12 A exposed to pool water  102  and open ends  12 B exposed to suction line  200 . More specifically, open ends  12 A are distributed about a periphery of housing  52 . When housing  52  is installed in sleeve  54 , open ends  12 A are located at the pool&#39;s bottom  300  and exposed to pool water  102  with each open end  12 A facing substantially radially outward with respect to the central longitudinal axis  52 B of housing  52 . 
     Top area  52 A can be smooth as illustrated in  FIG. 4 , or can present topographic features such as an undulating surface as shown in  FIG. 5  to further limit the possibility of covering all of open ends  12 A. This ensures that the full suction force applied via suction line  200  can never be applied fully to a body interacting with housing  52 . Top area  52 A between open ends  12 A can be made large enough to prevent coverage thereof by a human extremity or even larger body parts. Top area  52  can be rectangular (as shown) or any other regular or irregular shape without departing from the scope of the present invention. 
     The features and benefits provided by the above-described plate/plug  14  are incorporated into sleeve  54 . More specifically, sleeve  54  has side walls  54 B extending from annular flange  54 A and into suction line  200 . Side walls  54 B terminate in a plate  54 C having through holes  54 D. The length of sleeve  54  is such that plate  54 C is spaced apart from open ends  12 B defined by housing  52 . 
     To install safety system  50 , sleeve  54  is simply positioned in suction line  200  and housing  52  is dropped into sleeve  54 . Sleeve  54  can remain in place to provide a degree of entrapment protection when housing  52  is removed for cleaning, repair, or replacement. 
     Another retro fit embodiment is illustrated in  FIGS. 6 and 7  where a safety system  60  has a dome-like top with sloping sides  62 A- 62 D originating at a top  64 E and terminating above pool bottom  300 . Top  64 E could be smooth or present topographic features where it interfaces with pool water  102  without departing from the scope of the present invention. A flow sleeve  64  (i.e., analogous to sleeve  54  with elements  64 A- 64 D corresponding to elements  54 A- 54 D, respectively) is fitted in/sealed to suction line  200 . Each side  62 A- 62 D terminates at a peripheral region of housing  62  to define an opening  12 A of a closed channel  12  that is typically at least 3 feet in length as they are led through housing  62  to corresponding open ends  12 B in sleeve  64 . As in the previous embodiment, open ends  12 A face substantially radially outward with respect to the central longitudinal axis  62 F of housing  62 . The regions  62 G where adjacent sloping sides meet define walls (not shown) between open ends  12 A where such walls rest on annular flange  64 A. 
     Note that while each of the embodiments illustrated in  FIGS. 4-7  is rectangular, they could also be other shapes (e.g., round, triangular, octagonal, etc.) without departing from the scope of the present invention. Note also that while these embodiments depict open ends  12 A above pool bottom  300 , the present invention is not so limited as the various embodiments of the present invention could also be designed such that open ends  12 A reside just below pool bottom  300 . 
     Still another embodiment of a retrofit safety system is illustrated in  FIGS. 8 and 9 . The safety system&#39;s housing  72  has a solid top area  72 A large enough to prevent coverage by human extremities. Top area  72 A could be smooth or define topographic features. The upper periphery of housing  72  defines a number of open ends  12 A of channels  12  that helically wrap about or within the radial periphery of housing  72 . Once again, open ends  12 A face in substantially radially outward direction from the central longitudinal axis  72 B of housing  72 . If channels  12  are formed on the outside of housing  72 , then housing  72  is sized to form a sliding fit in sleeve  74  ( FIG. 9 ) such that the combination of housing  72  and side walls  74 B of sleeve  74  define distinct and closed channels  12 . Open ends  12 B at the end of channels  12  are located in sleeve  74  and spaced apart from plate  74 C. Note that while channels  12  are illustrated as helical in this embodiment, they could assume some other nonlinear path without departing from the scope of the present invention. Solid top area  72 A is shown to have approximately the same diameter as housing  72 , but may be larger if necessary to increase the distribution area of open ends  12 A depending on available space for housing  72 . 
     The flow housings described in the previous embodiments can be one-piece or multiple piece housings without departing from the scope of the present invention. In terms of a possible multiple piece housing,  FIGS. 10A and 10B  illustrate a two-piece flow housing  80  with a top half  80 A including partitions  82  and a bottom half  80 B including partitions  84 . When halves  80 A and  80 B are joined, partitions  82  and  84  are interlaced to define vertically-serpentining distinct closed channels  12  along with open ends  12 A and  12 B. For simplicity of illustration, only four closed channels  12  are illustrated. However, more than four could be used without departing from the scope of the present invention. Each closed channel  12  admits a flow  102 A of pool water  102  via its corresponding open end  12 A. Each flow  102 A follows a serpentine flow path that goes down one side of partition  82 , underneath partition  82 , between partitions  82 / 84 , over partition  84 , and down between partition  84  and a downward portion  81  of top half  80 A before finally exiting the channel&#39;s open end  12 B.  FIG. 11  depicts a similar embodiment with horizontally-serpentining closed channels  12 . Other multiple-piece designs could be used without departing from the scope of the present invention. In each of the  FIGS. 10 and 11  embodiments, a flow sleeve  86  (i.e., analogous to the flow sleeves described previously herein) is positioned in suction line  200  in the same fashion as in the previously-described embodiments. 
     The advantages of the present invention are numerous. A simple safety system is based on principles that can be applied in new or existing pool, spa, or any other fluid tank. The safety system distributes drain/recirculation suction openings and suction force over an area that prevents substantial coverage thereof when a human interacts therewith. Further, the system controls flow therethrough in a way that prevents entanglement of hair or clothing that might be sucked into the safety system. Still further, the flow sleeve&#39;s multiple-hole plate provides added protection against limb entrapment and injury in the event the safety system&#39;s flow housing is damaged or must be temporarily removed. 
     Although the invention has been described relative to a specific embodiment thereof, there are numerous variations and modifications that will be readily apparent to those skilled in the art in light of the above teachings. For example,  FIG. 12  illustrates an isolated view of a flow sleeve further instrumented with pressure sensors. More specifically, flow sleeve  54  has a pressure sensor  56 A disposed in sleeve  54  in a region thereof that is between plate  54 C and open ends  12 B (not shown) of a safety housing that would be installed in sleeve  54 . A second pressure sensor  56 B is disposed in one of through holes  54 D. Pressure sensors  56 A and  56 B can be used to measure a pressure differential between a fluid flow in sleeve  54  and that passing through plate  54 C. In this way, pressure sensors  56 A and  56 B can be used to develop a pressure differential measurement that indicates (i) an unobstructed flow through sleeve  54  when the pressure differential measurement is at or near zero, or (ii) an obstructed flow through sleeve  54  when the pressure differential measurement is some significant value. Sleeve  54  could also be instrumented with signal leads (e.g., within or along the walls of sleeve  54 )  58 A and  58 B coupled to pressure sensors  56 A and  56 B, respectively. Leads  58 A and  58 B could then be coupled to a controller (not shown) designed to automatically turn off a suction pump (coupled to the above-described suction line  200 ) when the pressure differential measurement was indicative of an obstructed flow. The pressure differential measurement could also be made using submersible wireless transducers. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described.