Pumps – Motor driven – Fluid motor
Reexamination Certificate
1999-08-09
2001-03-27
Walberg, Teresa (Department: 3742)
Pumps
Motor driven
Fluid motor
Reexamination Certificate
active
06206657
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to pumps for groundwater sampling and the like, and, more particularly, to automated air-operated bellows pumps for groundwater sampling and other applications.
BACKGROUND OF THE INVENTION
There does exist many types of submersible pumps for groundwater sampling and other uses.
FIG. 1
shows, generally at
100
, a typical prior-art configuration. Since devices of this kind are inserted down well holes, the unit consists of an outer cylindrical pump body
102
, typically constructed of stainless steel. The body includes a lower inlet end
104
and an upper outlet end
106
. An internal cylindrical bladder
108
, typically constructed of Teflon, partitions the interior of the pump body
102
into a gas-carrying section
110
, and a fluid-carrying section
112
within the bladder
108
.
A tube
114
having, perforations
116
, is generally positioned within the fluid-carrying section
112
, as shown. A lower check valve
120
is provided at the lower inlet end
104
to permit groundwater or like fluids to pass through the lower end
104
and into the tube
114
and fluid-carrying chamber
112
through perforations
116
. The check valve
120
also prevents the fluid from backflowing through the lower inlet
104
. An upper check valve
122
allows fluid from the fluid-carrying chamber
112
to be discharged through the upper end
106
by passing through apertures
116
and into the tube
114
. The upper check valve
122
also prevents the fluid from backflowing down into the pump interior.
Above ground, a controller
130
is provided having a conduit
132
in pneumatic communication with the gas-carrying section
110
within the pump body
102
. The apparatus operates by pressurizing and venting the gas within the chamber
110
, thereby compressing and expanding the bladder
108
, which is quite flexible, thereby forcing fluid within the chamber
112
out the upper end
106
through tube
114
by way of apertures
116
. More particularly, when the pump body is submerged, ground water or other fluid flows into the chamber
112
through tube
114
having apertures
116
through the lower end
104
, bypassing check valve
120
due to natural hydrostatic pressure.
When an actuating gas such as compressed air is driven through conduit
132
and into the gas-carrying section
110
, the bladder
108
is compressed and the lower check valve
120
is forced against the opening
104
, thereby forcing the fluid contained within the fluid-carrying section upwardly and out through the upper opening
106
, displacing check valve
122
in its path. The gas-carrying chamber
110
is then vented at ground level through controller
130
, permitting a fresh charge of ground water to again fill the fluid-carrying chamber
112
and tube
114
through perforations
116
, at which time another cycle may be started by compressing the bladder
108
.
Although a single controller
130
may be configured to control a multiplicity of similar pumps, the timing sequences for each pump must be optimized and stored to ensure the most efficient operation for each sampling station. The timing/cycling means within the controller therefore typically includes a 3-way valve associated with each pump to which it is connected. The 3-way valve is alternatively actuated and de-actuated to produce a pulsating flow to the bladder of each pump, wherein a compressed gas is applied via each conduit
132
, on which the 3-way valve changes state, enabling the gas contained within chamber
110
to be vented to atmosphere. The controller
130
must therefore include electronic, pneumatic or mechanical timing devices associated with each 3-way valve, in each pump, to ensure proper operation thereof.
Pumps of the type just described are used in a variety of applications, including the continuous collection of gasoline and other hazardous materials from aquifers, as well as occasional groundwater sampling. There is also a need for pumps used for more infrequent sampling, using a device sometimes referred to as a “bailor.” Originally, such devices assumed the form of a polyethylene or Teflon tube having a bottom end with a check ball. The device was lowered into a well, allowing liquid to trickle past the check ball until the tube was filled and the check ball was seated. The device was then removed form the well, the sample removed, and the rest of the device discarded.
By EPA mandate, the bailing process must remove three times the volume of a well before a sample is taken. This means that if the volume of the well is 50 gallons, 150 bailing operations must be taken prior to taking the actual sample. The time-consuming nature of this process led to the development of continuously cycling sampling pumps of the type described with reference to FIG.
1
. Even with these, however, the apparatus is expensive, and the bladder must be removed, typically requiring a meticulous dismantling of the pump body. The need therefore remains for an economical pump capable of repetitive sampling. Ideally, such a pump would include some form of collection cartridge that is easily removable, allowing the pump to be used for more infrequent sampling applications, including bailing.
SUMMARY OF THE INVENTION
The present invention improves upon pumps of the type used for groundwater sampling, including the removal of gasoline or other hazardous materials, by providing a cartridge which, in the preferred embodiment, is easily removable for bailing and other operations. The invention also preferably utilizes a bellows as opposed to the traditional bladder used for fluid collection, thereby providing a number of advantages over conventional designs, including the potential for truly automatic operation and higher throughput. Although the drawings and associated descriptions refer to a corrugated bellows, it will be apparent to one of skill in the art that other types of bellows, including convoluted arrangements, may alternatively be utilized. The open end of the bellows or other collection device according to the invention is also preferably positioned with the open end oriented upwardly during normal operation, thereby allowing trapped gas to escape.
An air-operated pump for groundwater sampling and other applications according to the invention includes a submersible pump body having a fluid inlet. Air-supply line and fluid-discharge lines are coupled to the pump body from an above-ground location, and a corrugated bellows or alternative collection cartridge is disposed within the pump body. The fluid-collection device features a closed end and an open end which is preferably oriented upwardly to allow trapped gas to escape. The bellows or alternative collection device is operable through pressurization be the air-supply line between a refill state, wherein fluid is drawn into the pump body through the fluid inlet, and a discharge state wherein fluid is forced out of the pump body through the discharge line.
In the preferred embodiment, the pump further includes a pump head having a lower, fluid-receiving port, and a shell removably attachable to the pump head. The bellows or alternative fluid-receiving device is disposed within the shell and removable attachable to the fluid-receiving port on the pump head. The fluid-collection cartridge may be removably attachable to the pump head through a threaded fitting, a press fitting, or other means providing an appropriate seal to the surrounding environment.
REFERENCES:
patent: 2564198 (1951-08-01), Elkins
patent: 3113455 (1963-12-01), Sloan et al.
patent: 4669554 (1987-06-01), Cordry
patent: 4717473 (1988-01-01), Burge et al.
patent: 4943210 (1990-07-01), Bailey, Jr. et al.
patent: 4974674 (1990-12-01), Wells
patent: 5027902 (1991-07-01), Dickinson
patent: 5099920 (1992-03-01), Warburton et al.
patent: 5293934 (1994-03-01), Burge
patent: 5708220 (1998-01-01), Burge
Gifford Krass Groh Sprinkle Anderson & Citkowski PC
Patel Vinod D
Walberg Teresa
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