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Overview
Operation
Tubing, Foot Valves and Surge Blocks
High Quality VOC Samples
Flow Rates
Overview
The Model 404 WaTerra Pump is a simple, reliable inertial pump which uses an age old, proven technology, in an elegant manner uniquely adapted to the needs of modern groundwater monitoring.
The pump consists of a riser tube with a one-way valve at the foot and a surface pumping mechanism. The valve allows water to enter the tubing as it is pushed downwards and retains the water when the tube is pulled upwards again.
The inertia of the water itself provides the force to carry it up to the surface whenever the tube is being pumped up and down. The water travels in a continuous column, with little disturbance, thus retaining volatiles.
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Operation
To obtain a sample, the tube and foot valve are lowered to the desired depth and rapidly pumped up and down, either manually or mechanically. The lightweight WaTerra Pump Handle is used for manual pumping and is inexpensive and highly portable. This makes it excellent for use in remote locations. The electric or gasoline pump control units are ideal for larger volumes of water, higher pumping rates, and longer time periods. All provide excellent well development and efficient purging and sampling of monitoring wells.
Ideal for Dedication
- Low cost - little more than a bailer
- Avoids cross-well contamination
- Avoids costly field blanks
- Eliminates repeated pump decontamination
Versatile
- Excellent in silty/sandy environments
- Ideal for well development
- Operates to 250+ ft. (75+ m)
- For wells with 0.5" - 6" ID (12mm - 150mm ID)
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Tubing, Foot Valves and Surge Blocks
High Density polyethylene tubing 5/8" O.D. x 1/2" I.D. (16mm O.D.) is the tubing most frequently used. 1" O.D. x 0.814" I.D. (25mm O.D.) HDPE is available for high capacity applications, and tubing as small as 3/8" O.D. (10mm) for narrow diameter applications. The tubing comes in coils 100', 200' or 500' long. TeflonŽ tubing is also available.
Foot Valves are available in Delrin or stainless steel, in a variety of sizes from 3/8" to 1 - 1/4" (10mm - 31 mm) diameters. Tapered threads enable the foot valve to self tap onto either end of the tubing.
Surge Blocks create a strong churning effect which helps remove silt and fine sand during well development. Available to fit any foot valve and wells up to 6" (150mm) diameter.
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High Quality VOC Samples
To obtain excellent VOC samples, all that is required is to use about 8 feet of 1/4" diameter (2.5m x 6mm) sampling tube. After purging, this is inserted into the riser tube leaving about 1 ft. (30cm) protruding. Develop a steady water flow and upon ceasing, the sample tube will continue to act as a gravity flow siphon and produce an undisturbed VOC sample.
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Flow Rates
Flow rate is a function of the momentum generated in the tubing. It varies with tubing length, submergence depth of the foot valve, flexing of the tube, and with the pumping rate.
- Up to 2 gal/min with hand pump handle and flexible tube.
- Up to 4 gal/min with a control unit and 1" tubing.
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