Patent Application
20100213396
This invention is generally directed to a throttle valve used to regulate water flow when recharging aquifers.
Many water districts and communities have realized the need and value of maintaining the water level and storage capacity of aquifers that provide drinking and irrigation water. Furthermore, due to high demand and to variability of supply and demand, it is desirable that an adequate reserve capacity of water storage facilities be maintained to provide for extended peak demands, droughts and explosive growth of new customers. Reserve storage capacity to provide for such events in capital facilities is prohibitively expensive to construct and difficult to justify. Accordingly, capital facilities typically lag behind demand.
In an effort to reduce these capital facility costs, water resource engineers have become interested in the concept of replacing or storing large volumes of treated water in aquifers during periods when both water and facility capacity are available to provide water required to recharge aquifers. The concept replacing the water pumped from the aquifer or seasonal storage is called Aquifer Storage Recovery or ASR. This scenario is a cost effective alternative to conventional approaches to the expansion of water supply, treatment, distribution and water storage capital facilities. In general, a well based system or one that is partially well based is a system in which wells can be used for both recharge and recovery. In recovery, the water may require only disinfection. Recharge wells may be through existing wells or through dedicated recharge wells.
In addition to reduction in facilities expansion costs, other advantages favor recharge technology. In coastal areas reduced levels in aquifer water may permit the intrusion of salt water which can result in the destruction of the fresh water supply. In these areas, a mound of recharged fresh water is placed, through balanced flow control, in the aquifer forming a uniform curtain or barrier between salt water and fresh water, effectively preventing salt water intrusion. At times, this volume of water can be used to meet seasonal peak demands.
Such storage and water resource techniques have proven extremely advantageous and cost effective in areas where declining ground water levels have reduced or left wells nearly non-productive.
Another application of this type of device is the use in ground water remediation. In areas where existing ground water supplies are threatened or have been contaminated, flow control devices are effective in managing an effective program. Once the water is extracted and treated, this type of flow control device is able to balance the flow in a series of recharge wells to provide a uniform curtain of water, placing the water in the aquifer evenly and uniformly.
Well recharging is also effective where substantial reserves are necessary to improve system reliability in the event of a catastrophic loss of a primary water supply or in communities where strategically located reserves are required to ensure an adequate balance in system flows during peak demand.
Although there are obvious benefits to be obtained from recharging existing production water wells or in constructing new water storage recovery wells, in many applications problems have been encountered with air entrapment in the recharge water causing air binding of the aquifer. Air binding effectively decreases the permeability of the aquifer, thereby decreasing the effectiveness of the recharging operations. Such air entrapment is most frequently encountered in areas or localities where one or more of three conditions exist. These conditions may be encountered when: (1) the recharge water must drop a considerable distance from the well head to the static water level; (2) when the recharge flow is relatively low; and (3) where the specific capacity of the well is relatively high. The foregoing conditions have resulted in the cascading of water in the recharge column or drop pipe, thereby entrapping large quantities of air which is carried into the well and outwardly into the aquifer. The entrapped air can effectively plug or seal the aquifer, a condition known as air fouling, resulting in substantially lower permeability and storage capacity.
The foregoing problem has been addressed in U.S. Pat. Nos. 5,503,363; 5,618,022; 5,871,200 and 6,073,906; however there is some concern that lateral ejection of water from the outlet ports will damage the recharge well by creating debris that will clog wells and damage downhole pumps used to recycle recharge water.
In view of the aforementioned concerns a recharge pipe for mounting in a recharge well has a pipe section with a valve mounted in an intermediate pipe portion. The valve has an upper end for connecting through the recharge pipe to a source of pressurized water and a lower end for coupling with a flow inhibitor. A plurality of outlet ports are provided in the intermediate portion, through which outlet ports pressurized water flows into the aquifer.
A sleeve is positioned over at least the intermediate pipe section, the sleeve being movable between a first position in which the sleeve covers the outlet ports to block the flow of water out of the outlet ports and a second position in which the sleeve at least partially uncovers the outlet ports to throttle water flowing therefrom into the aquifer. A throttle skirt extends axially from the sleeve. The throttle skirt has a length sufficient to overlie the outlet ports and is in radial spaced relation to the intermediate portion of the pipe section. A downwardly facing opening is defined by the throttle skirt to direct water passing through the openings in the intermediate portion into the well in the axial direction of the pipe section to fill the aquifer. An actuator in operative relation with the sleeve, axially translates the sleeve so as to minimize cascading of refill water flowing down the recharge pipe.
In another aspect of the downhole flow control, the actuator is hydraulic.
In still another aspect of the downhole flow control, the outlet ports are spaced elongated slots extending axially with respect to the pipe section.
In still another aspect of the downhole flow control, the outlet ports are four to twelve in number.
In another aspect of the downhole flow control, the outlet ports are located axially below the actuator so that the sliding sleeve progressively closes the outlets upon being lowered to cover the outlet ports.
In still another aspect of the downhole flow control, the actuator is hydraulic and comprises a double acting hydraulic actuator associated with the sleeve for moving the sleeve between the first and second positions to keep the recharge pipe filled with water, whereby air does not become entrained in the water as the water moves through the recharge pipe to enter the aquifer.
In a further aspect of the downhole flow control, the valve is connected at the upper end thereof directly to the recharge pipe and is connected at the lower end thereof to a vertical downhole pump, the vertical downhole pump having a foot valve at the other end thereof, the flow inhibitor being a check valve.
In a further aspect of the downhole flow control, the valve is configured as a pipe section and is connected at the upper end thereof to the recharge pipe, the flow inhibitor being a blind flange.
Various other features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which the reference characters designate the same or similar parts throughout the several views, and wherein:
Referring now to
As will be explained hereinafter, a difficulty with currently available arrangements for recharging aquifers 11 is that the walls 18 of the recharge wells 10 can be eroded by lateral discharge of pressurized water 13 that displaces portions of the walls into the aquifer, thus potentially clogging the recharge system. This can occur by debris from the walls 18 of the well 10 clogging the aquifer 11 itself, or from the walls of the well generating debris that clogs a return pump at location 15. Applicant has now configured the recharged pipe 12 to address this concern by having a downhole flow control 20 that directs recharge water 13 downwardly in the direction of the pipe axis 21, rather than laterally against the side wall 18 of the recharge well 10.
As is seen in
When the valve 28 is closed as in
The throttle skirt 46 is fixed to a valve collar 50 which is slidably mounted around the intermediate sections 34 of the pipe section 30 for movement in the direction of the longitudinal axis 47 so as to cover and uncover the outlet ports 40, the outlet ports 40 being shown covered by the valve collar 50 in
Threaded to the upper end 59 of the outlet cover 50 is an annular sleeve 62 that is sealed by a sealing collar 64 to define first and second chambers 68 and 69 therein which are separated by a partition 72 fixed therebetween to the intermediate portion 34 of the pipe section 30. Connected to the chamber 68 is a first port 74 connected to a first hydraulic line 75 and connected to the upper chamber 69 is a second hydraulic port 76 connected to a second hydraulic line 77. Hydraulic line 75 is connected to a hydraulic fitting 80 leading outside the pipe section 30, while the hydraulic line 77 is connected to a pipe fitting 82 also leading outside the pipe section 30. Hydraulic hoses (not shown) extend to the ground surface for pressurizing and relieving the chambers 68 and 69 that move the sealing collar 64.
In
The open area of the slot 40 can be increased to include the entire length of the outlet port 40 as is shown in
The length of the outlets 40 can slowly be increased at the start of a recharge cycle to eliminate, or substantially eliminate, the rate of well recharge so as to avoid cascading of water 13 in the recharge pipe 12, which cascading traps air that can pass through the outlet ports 40 and be accumulated in the aquifer 11 so as to prevent further entry of recharge water. In a relatively short time such an accumulation of air can nullify an attempt to recharge an aquifer 11 with surface water 13. The valve sleeve 50 eliminates this problem.
From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing form the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.
