DGSI. Durham Geo Slope Indicator

Skimmer Assembly

The skimmer is attached to the bottom of the F.A.P. Plus™ pump and is used to separate the product from the water in the well. Depending on your site conditions, three types of skimmers are available: standard, high viscosity and density skimmers. The skimmer selection table will help you select the proper skimmer for your site.How do I select the most appropriate skimmer system? The most important elements in choosing the F.A.P. Plus™ system will be your water table fluctuations, product viscosity, type of product, well diameter and amount of product present. Filling the remediation site assessment form will help you define all relevant your site conditions.

a. Standard Skimmer (TR-517)

Standard Skimmer
Skimmer Assembly

The standard skimmer is used to recover gasoline, jet fuel and most diesel fuels. It combines a density float, a special hydrophobic element, a product bypass, a hollow guide rod and a coiled hose. The center guide rod allows the skimmer to travel freely in response to the water table changes. The skimmer is designed to float with the inlet positioned at the water/product interface automatically providing 36” of skimmer travel. The density float is used to position the special hydrophobic element — the skimmer inlet — at the product water interface. The hydrophobic element uses a special micron pore size that is based on surface tension, allowing only product to pass. A larger pore size is available for use with higher viscosity products such as weathered diesel. Pumping rates through the hydrophobic element will be approximately 100 gallons per day.

Tech Tip: The larger micron-sized elements may allow a small percentage of water to pass.

The bypass element is attached to the top of the hydrophobic element and allows the product to enter the skimmer directly when the product layer is greater than 2 inches. Recovery rates through the bypass element are approximately 300 gallons per day.

The complete skimmer element is connected to the bottom of the guide rod by a coiled polyurethane hose. This coiled hose can accommodate water level changes of up to 36 in automatically maintaining the skimmer intake at the water/product interface. A minimum distance of 24 in from the bottom of the well to the water/product interface is required when using the TR-517. The TR-51711 requires a minimum of 18 in and provides 24 in of travel.

The skimmer can also be configured as a passive device by attaching a quick connect canister on the bottom of the skimmer, providing greater flexibility for free product recovery projects. See Passive Skimmer.

Maintenance: Biofouling may occur because the hydrophobic element is positioned at the air/product interface. If fouling occurs, the element can be cleaned using a soft brush or replaced by unthreading the bypass element and installing a new hydrophobic element.

TR-517
F.A.P. Plus Skimmer, 36" travel (min. 24" travel required)
TR-51718 F.A.P. Plus Skimmer, 18" travel (min. 18" travel required)
TR-51711 F.A.P. Plus Skimmer, 24" travel (min. 18" travel required)

 

 

 

 

High-Viscosity Skimmer
High-Viscosity Skimmers

b. High-Viscosity Skimmer (TR-70410)

This skimmer is used when the product has a viscosity higher than 80 SSU, such as oils. The 4 in high viscosity skimmer uses the same design as the TR-517, less the hydrophobic and bypass elements. The skimmer has a 30 in travel and a specific gravity of 0.95, allowing it to float at the water/ product interface. The product collects on the top of the skimmer inlet and, from there, is pumped to the surface. In normal applications the skimmer will remove product down to a ¼ in to ½ in product layer. The skimmer can be adjusted in the field to remove the product even further and attain a thinner layer.

TR-70410
4" High Viscosity Rod Skimmer (30" travel)

 

 

 

 

c. Density Skimmers (TR-704, TR-706, TR-712)

density skimmers
Density Skimmers

Density skimmers are used when there is less than 18 inches of fluid from the bottom of the well to the water/product interface. These skimmers have a specific gravity of 0.95 and float in the water with the top inlet just above the product/water interface. The skimmers have an effective travel of 24 inches. The 2 in and 4 in sizes are for use in well casings with these nominal inside diameters. The 6 in and 12 in models are self-supporting and may be used in large diameter wells, open excavations and open water applications.

TR-702 2'' Density Skimmer (1.65" dia.)
TR-704 4'' Density Skimmer (3.5" dia.)
TR-706 6'' Density Skimmer (5.5" dia.)
TR-712 12" Density Skimmer (11.5" dia.)