Patent Publication Number: US-2002007951-A1

Title: Well flow controller

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
     [0001] This application claims the benefit of the file date of the earlier-filed provisional application, No. 60/211,947, filed on Jun. 16, 2000. 
    
    
     
       STATEMENT REGARDING FED SPONSORED R&amp;D  
       [0002] None.  
       REFERENCE TO SEQUENTIAL LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX  
       [0003] None.  
       BACKGROUND OF THE INVENTION  
       [0004] The present invention relates to a well. Wells are used in the environmental and water supply industries, among other things, to 1) collect samples of groundwater for chemical analysis, and 2) provide data used in estimating aquifer parameters such as hydraulic conductivity (K), which is a measure of the ability of the aquifer matrix to transmit water. A typical well is comprised of a slotted section of pipe (the “well screen”) located at the bottom of the well, and sections of solid “riser” pipe which thread onto the well screen and each other to bring the well to the ground surface. The slots in the well screen are narrow enough (on the order of hundredths of an inch) to keep out the soil particles but allow in groundwater. If the well screen is located beneath the water table, groundwater entering the well screen will flow up the riser pipe until it reaches equilibrium. The present invention provides a mechanism for controlling the flow of groundwater into a well.  
       BRIEF SUMMARY OF THE INVENTION  
       [0005] The present invention is a PVC unit, which threads onto the well between the well screen and the riser pipe, that can be manually closed to prevent groundwater from entering the riser pipe; or manually opened to allow groundwater into the riser pipe. The primary advantages of the invention are realized in two fields of hydrogeology: 1) groundwater sampling; and 2) aquifer characterization.  
       [0006] The advantage in the area of groundwater sampling stems from the ability to control the flow of groundwater into a well. Conventional wells allows groundwater into the riser pipe to the level of equilibrium. Equilibrium is a function of the head (or pressure) at the well screen. Water will flow from areas of high head to areas of low head. Groundwater beneath the water table is typically under greater head than groundwater at or near the water table. Therefore, groundwater entering a well screen located beneath the water table will flow up the riser pipe until the head within the riser pipe equals the head at the well screen. At this point equilibrium is achieved.  
       [0007] Between groundwater sampling events, standing water in a riser pipe may be there for weeks, months or longer, and it is not considered representative of the groundwater outside of the well screen. At the time of sampling, up to six volumes of this standing water must first be removed in a procedure referred to as “purging” the well. Purging removes the standing water, which may be chemically different from the groundwater. In many cases the purged water must be treated to remove the contaminant(s) before it can be discharged. This treatment usually takes place off-site and can be costly. The present invention essentially eliminates the necessity of purging since it controls the flow of groundwater into the well. The present invention can be opened at the time of sampling, and then closed when a sufficient volume of groundwater has entered the well. This incoming water is representative of the groundwater outside the well screen. Once the sample has been collected, the remaining water in the riser pipe (a fraction of the typical standing water) can be purged and the riser pipe can be left empty until the next sampling event.  
       [0008] The advantage of the present invention in the area of aquifer matrix characterization stems from the ability to allow groundwater to “instantaneously” flow into the riser pipe. By determining the rate of the in flowing water, K can be estimated. K is an important parameter in both contaminant hydrogeology and water supply. It is an indication of the transmissivity of the aquifer matrix material, which is essential for engineering groundwater extraction wells. The present invention eliminates the necessity of large-diameter wells and expensive pumps to lower the water surface in the well. Once the invention is installed, the well screen can be opened and the rate at which the head reaches equilibrium can be used to estimate K. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0009]FIG. 1 is a cross-sectional side view of the typical components of a well including the well screen and the riser pipe. The well screen depicted is five feet in length and it is located fifty feet beneath the water table. A forty five foot standing water column exists above the well screen.  
     [0010]FIG. 2 is a cross-sectional side view of a well equipped with the present invention. The PVC lid is in the closed position.  
     [0011]FIG. 3 is a cross-sectional side view of a well equipped with the present invention. The PVC lid is in the opened position.  
     [0012]FIG. 4 is a cross-sectional side view of the present invention with the PVC lid in the closed position.  
     [0013]FIG. 5 is a cross-sectional side view of the present invention with the PVC lid in the opened position.  
     [0014]FIG. 6 is a cross-sectional front view of the present invention with the PVC lid in the closed position.  
     [0015]FIG. 7 is cross-sectional front view of the present invention with the PVC lid in the opened position. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0016] The present invention provides a mechanism for controlling the flow of groundwater into a well. Groundwater enters the well through the well screen  1 . The well screen is typically located at depth and is attached to riser pipes  2  which are threaded  3  onto the well screen to bring the well to the ground surface. The present invention incorporates a PVC chamber  4 , a PVC lid  5 , a gasket  6 , a fulcrum  7 , a lever  8 , a wire to open the PVC lid  9 , and a wire to close the PVC lid  10 . The chamber is threaded on both ends  11  to accept the threads of standard well screens and riser pipes.  
     [0017] The gasket and the wire for closing the PVC lid are secured to the top of the PVC lid (in the closed position). The wires for opening and closing the PVC lid extend up the riser pipe to the ground surface where they can be manually operated.). The wire for closing the PVC is used to pull the PVC lid upward into the closed position, which compresses the gasket against the gasket seat  12 . The wire is then secured at the top of the well to keep the seal. The tension on  10 . The chamber is threaded on both ends  11  to accept the threads of standard well screens and riser pipes.  
     [0018] The gasket and the wire for closing the PVC lid are secured to the top of the PVC lid (in the closed position). The wires for opening and closing the PVC lid extend up the riser pipe to the ground surface where they can be manually operated.). The wire for closing the PVC is used to pull the PVC lid upward into the closed position, which compresses the gasket against the gasket seat  12 . The wire is then secured at the top of the well to keep the seal. The tension on the wire combined with the head pressure against the bottom of the PVC lid sufficiently compresses the gasket to create a water-tight seal. To open the PVC lid and allow groundwater into the riser, the tension on the wire for closing the PVC lid is released, and tension is applied to the wire for opening the PVC lid. This causes the lever to pivot around the fulcrum, which opens the PVC lid. The lever is open in the middle  13  to reduce the upward pressure exerted on it by the in flowing groundwater.