Variable orifice valve

The Variable Orifice Valve is disclosed and the preferred embodiment of a hydraulically actuated device that permits the calibrated throttling of water used in an Aquifer Storage and Recovery (ASR). ASR is the storage of treated drinking water in an aquifer during periods of surplus water for recovery during peak demands. This device is installed below the static water level and at or near the bottom of the column pipe in the recharge well. The size of the orifice and the flow of water is varied by the axial adjustment of a hydraulic piston. The axial position of the piston is controlled by a hydraulic actuator competed through steel tubing to a hydraulic pump at the well head. The flow is monitored by using a flow meter and pressure gage in the hydraulic fluid passageway. The desired flow is set by adjusting the Variable Orifice Valve hydraulically while monitoring the flow. The operator may adjust the flow of water to any increment within the range of the valve.

BACKGROUND-FIELD OF INVENTION 
This disclosure relates to Aquifer Storage and Recovery (ASR) of water 
beating aquifers and flow control devices used in optimizing the rate of 
recharge. 
BACKGROUND OF INVENTION 
This invention is the result of the determination that an Artificial 
Recharge Well used in the Acquifer Storage and Recovery (ASR) in the 
storage of drinking water can and will require injection rate to be varied 
during the well's life span to allow optimization of the well's potential 
under changing background conditions. 
In the arid western portions of the United States the natural recharge 
rates are falling behind the production rates, the result is the gradual 
lowering of the static water levels in the aquifers. An aquifer is natures 
version of a water reservoir. Artificial Recharge of aquifers is an 
activity that is an acceptable means of replacing the water stored in an 
aquifer and restores the static water levels. An Artificial Recharge Well 
is essentially a production well used in reverse or a means of refilling 
the aquifer. Artificial recharge of ground water aquifers is also done to 
bank or store extra water for summer months when peak demands are greater 
than the surface water infrastructure can supply. Typically, in this 
situation, the summer or production season is 3-4 months long and the 
recharge season is for the remainder of the year. 
The recharge rate of an Artificial Recharge Well is normally controlled by 
a single size orifice plate that is designed for specific recharge rate. 
The orifice plate is installed at/or near the bottom of the injection 
piping and provides for flow control and a means to maintain the column 
pipe full of water, thus eliminating the potential of bacterial 
development and most or all of the air and bubbles formed by the free 
falling water. The free falling water aerates the groundwater and forms 
bubbles that are forced into the sands of the aquifer. The bubbles cling 
to the sand particles effectively increasing the size of each sand 
particle grain. This action effectively closes off the permeability of the 
aquifer and gradually reduces the amount of water that may be recharged. 
In some cases the well has been rendered useless. The recharge rate is 
determined at the time of drilling of the well and provides a starting 
point for the design recharge rate. In most cases the recharge rate will 
eventually need to be increased or decreased to optimize the injection 
rate and period to maximize the volume of water stored. To change the 
recharge rate in a typical recharge well it is necessary to pull the 
column pipe and change the orifice plate. This is an expensive process 
costing $10,000 to $12,000 ('94$) and will take the well out of service. 
This disclosure reveals a devise that eliminates the need to pull and 
replace the orifice plate to obtain a different flow rate. 
BRIEF DESCRIPTION OF THE INVENTION 
The following is a more descriptive characterization of the preferred 
embodiment shown in FIG. 1. 
This invention is a Variable Orifice Valve or Linear Hydraulic Flow Control 
Device that permits calibrated throttling or flow adjustments from the 
well head and eliminate the process of pulling the well column pipe to 
replace the orifice plate. The flow is adjusted by axially positioning a 
tapered piston or a tapered shaped restrictive valving portion in an 
orifice plate or circular opening. The axial position is determined by a 
hydraulic actuator at the valve. The actuator is connected through a steel 
tubing to a hydraulic pump at the well head. The desired flow is set or 
adjusted by monitoring a flow meter or flow monitoring means and 
hydraulically positioning the piston. To decrease the water flow the 
piston is hydraulically moved axially and vertically towards the orifice 
plate, therefor closing the valve. To increase the flow, hydraulic fluid 
is released from the actuator, repositioning the piston away from the 
orifice plate, causing the valve to open. Incremental adjustments of flow 
can be made within the entire range of the valve. 
A linear hydraulic flow control device for determining a desired flow rate, 
comprising a hydraulic fluid passageway housing, an orifice plate having a 
circular opening therein is disposed within said fluid passageway housing 
and being secured thereto, a plurality of equally spaced guide mounting 
plates disposed within said passageway housing, said guide mounting plates 
having one end secured to the surface face of said mounting plate, a 
hydraulic piston control device disposed within said passageway housing 
and movably guided between said guide mounting plates, said control device 
having tapered portions disposed at each end of said control device and an 
intermediate circular portion therebetween, one of said ends having a 
tapered shaped restrictive valving portion an the intermediate portion 
having a circular valving portion for variably controlling a fluid flow 
rate through said circular opening by changing the size of said circular 
opening, as said tapered valving portion and said intermediate valving 
portion are moved through said circular opening, an adjustable hydraulic 
actuator is secured to the other of said tapered ends within said fluid 
passageway housing, said hydraulic actuator having a portion secured to 
the other ends of said guide mounting plates, said hydraulic actuator 
adjustable controls the movement of said control device valving portions 
relative to said circular opening to permit a desired flow rate, where by 
the movement of said control device through said guide mounting plates 
minimizes flow turbulence through said circular opening; and means for 
adjusting the hydraulic actuator for setting the desired flow rate to any 
increment within the range of the movement of said control device valving 
portions. 
The linear hydraulic control device, as previously recited, in which the 
guide mounting plates serve as straightening vanes in the fluid passageway 
housing, said vanes act to stabilize the turbulent flow created by said 
control device valving portions and the circular opening during certain 
flow conditions. 
The linear hydraulic flow device as previously recited, in which said 
hydraulic piston is adjusted by a volume of hydraulic fluid through a 
small diameter tube, a three way valve and any one of a manual pump and an 
electrically driven hydraulic pump, connected in series, and being 
cooperatively associated with said hydraulic actuator for determining the 
desired flow rate of said control device valving portions relative to said 
circular opening a flow monitoring means responsive to said flow rate 
within said fluid passageway housing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Attention is first directed to FIG. 1, this illustrates the embodiment of 
this invention, A Variable Orifice Valve or Linear Hydraulic Flow Control 
Device, FIG. 3 schematic illustrates the hydraulic system used as a 
control apparatus. The Variable Orifice Valve is operated under hydraulic 
pressure. In the event of a loss of hydraulic fluid the valve will return 
to the open position or fail safe position. In the event of a loss of 
hydraulic fluid the hydraulic fluid is a bio-degradable glycol and 
potable, therefor is not an environmental hazard. The Variable Orifice 
Valve is generally identified by the number 16. To this end, the apparatus 
incorporates a fluid line 9 which delivers hydraulic fluid under pressure 
to the hydraulic actuator or slave cylinder 5 which moves the piston 1 
towards the orifice plate 2 to reduce the flow through the valve. FIG. 2 
shows the valve in the closed position. A unique feature of this valve is 
that the water flow is never shut off completely nor can the piston 1 be 
forced into the orifice plate 2, which would result in a catastrophic 
failure. This possibility, is a most likely scenario with an inexperienced 
operator or an individual who is not paying attention to what they are 
doing while adjusting the flow rate. The initial sizing of a valve 
provides a clearance between the piston 1 and the orifice plate 2. The 
valve is throttled or adjusted within the design range by observing a flow 
monitoring means or flow meter, a part of the normal water piping that 
supplies the well. The meter is used to totalize and record the flow of 
recharge water, a requirement by State Engineers in the west. The valve is 
individually sized and operate within a minimum design range, to 150% of 
maximum flow rate. The initial flow rate is determined by a hydrologist 
from aquifer test data acquired from the well at the time of drilling. To 
operate the Variable Orifice Valve and to decrease the flow valve 13 is 
closed and pump 14 is operated taking hydraulic fluid from the reservoir 
forcing hydraulic fluid through line 9 to the actuator 5, moving the 
piston I axially towards the orifice plate 2, reducing the size of the 
orifice plate 2 opening. To increase the flow through the Variable Orifice 
Valve 16, valve 13, FIG. 3 is opened, the hydraulic fluid returns through 
line 9 to the hydraulic storage tank 14 by the pressure of the hydraulic 
actuator 5 and the force of the flowing water flowing across the piston. 
Due to the wet environment that this valve operates in the piston 1, 
orifice plate 2, mounting plate 3, mounting bushing 4, hydraulic actuator 
5 and locking collar 6 are made from a highly corrosion resistant steel. 
The threaded couplings 8 and the hydraulic fluid passageway 7 are steel 
items normally used in the column pipe of water wells.