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| Double Valve Pump |
| Model 408 |
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| Description |
The Solinst Double Valve Pump (DVP) is a pneumatic drive pump that allows consistent, high quality samples. It has been field proven in thousands of applications. It offers excellent performance and reliability. No bladder replacement is required, and the Double Valve Pump provides higher pumping rates than with the Solinst Integra® Bladder Pump. There is a selection of sizes and materials, variable flow rates, and it is field serviceable. The DVP is suitable for low flow or regular flow sampling. The stainless steel pumps can operate to depths of 500 ft (150 m) and the PVC Double Valve Pump can operate to depths of 100 ft (30 m). |
| Features |
| Low Cost PVC This makes dedication more feasible for projects where budgets are tight. The lower capital cost allows several PVC pumps to be dedicated for the cost of one portable stainless steel pump. Dedicated pumps also save on field decontamination times and costs. A weight may be used to overcome buoyancy. PVC pumps are also useful for applications where stainless steel is unsuitable, such as:
Everything is easily accessible; replaceable and with interchangeable parts. All components can be cleaned with mild detergent or non-phosphate soap. Survives Dry Pumping, Dirty Air and Sand Pumps are not damaged by operation in sediment laden water, or in dry pumping conditions. |
| Applications |
| Low Flow Sampling Gives excellent VOC retention, comparable with bladder pump results. When using the Solinst Model 466 Electronic Pump Controller, the DVP can be adjusted to provide a continuous output of 100 ml/min or less. Non-Vertical Applications Operates effectively at almost any angle and can be placed under landfills, tailings, storage tanks or plumes. Leachate/Product Pumping Pneumatic drive pumps are well suited for pumping contaminant liquids. High solids content, solvents, hydrocarbons, and other chemicals are easily and economically pumped. |
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| Dedicated and Portable Systems |
| For long term monitoring it is best to dedicate the pumps to
reduce sampling time and avoid cross-contamination. Dedicated
well caps are designed for ease of use. Caps easily slip onto
2" or 4" wells, and have quick-connect fittings for the drive and
sample tubing. For less frequent sampling, reel mounted portable systems allow access to multiple monitoring wells, even in remote locations. The reel mounted portable units are free-standing with a convenient carrying handle. They can be made for almost any size or depth of application. |
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| Pump Operation |
| When the pump is placed in a well or borehole, water rises
inside the pump and the tubing to static level. Gas supplied
from the Controller pushes down on the water column
contained in the drive line tubing, closing the check valve at
the base of the pump. This forces water up the sample line
tubing. A vent period, during which the gas is released, allows hydrostatic pressure to refill the pump and drive line with sample water. The top check valve prevents water in the sample line from falling back into the pump body. This pressurization and vent cycle is repeated to bring water to the surface. For proper collection of volatiles, the pressure applied must never be high enough, nor the drive period long enough, to enable gas to enter the body of the pump and aerate the sample. If operated properly, “air” will never come in contact with the sample water, which produces high quality VOC samples comparable to those of a bladder pump. Flow rates vary with depth of pump below surface, depth below water level, size of drive and sample tubing, drive and vent cycle times, gas pressure applied, aquifer recharge, and size of pump body. |
| Electronic Pump Controller |
| The Model 466 Electronic Control Unit uses 8 AA batteries that
provide up to 30 hours of continuous use. The standard Model
466 gives up to 160 psi. A higher pressure unit providing up to
250 psi. is also available.
The Solinst Control Unit is fully automatic with preset sample modes to give a variety of useful drive and vent cycles. These can be further adjusted manually to optimize the flow. It allows faster purge rates and precise low flow to ensure a representative sample at 100 ml/min or less when sampling for VOCs. The convenient box is rugged and suitable for all environments. Quick-connect fittings allow easy, instant attachment to dedicated well caps or portable reel units. |
| Size and Material Options |
Solinst offers Double Valve Pumps in either 316 stainless steel
with Viton® o-rings, or in PVC with a polyethylene filter. The
two standard pump body sizes are:
Standard dedicated systems use 1/4" (6 mm) sample and 3/8" (10 mm) drive LDPE tubing. Portable systems use dual 1/4 (6 mm) skip-bonded LDPE lined with Teflon®. Adaptors for both 1/4" and 3/8" (6 mm and 10 mm) tubing are included. The Micro Double Valve Pump is a flexible, 3/8” (10 mm) diameter, Teflon Pump. It is ideal for low flow sampling in narrow applications. |
| Accessories |
| 12 Volt Air Compressor: Portable, designed to operate
using a vehicle’s battery. Ideal for field use, especially low flow
applications of less than 100 ft (30 m) depth. Packers: Save time and reduce costs by minimizing the volume of water purged. In-line Disposable Filters: 0.45μm, with 700 cm2 filter area. Tag Line: Convenient reel-mounted marked cable, for depth discrete pump support. |
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