Pressurized Disposable Bailers
This special disposable bailer provides the convenience of using in-line dispos-a-filters™ in the field even when pumps are not available.  By using a pneumatic hand pump you can filter your samples directly from the disposable bailer, saving time while maintaining sample integrity.  Each disposable bailers come complete with barbed hose adapters for attaching the hand pump to the top of the bailers, and special adapters with a notched thread to be used with a dispos-a-filter™ at the bottom.  In order to displace the check ball and establish a smooth flow, an additional large barbed removal device is included for bottom emptying without filtering.

About Disposable Bailers
Disposable bailers are a type of grab sampler used in ground water monitoring wells to retrieve a water sample from below the ground surface.  Disposable bailers, as a generic group, consist of a hollow tube with a check valve at the bottom and a handle at the top.  To retrieve a water sample from a well, a tether cord is attached to the handle at the top of the disposable bailer and the bailer is lowered into the well where it contacts the groundwater.

The weight of the disposable bailers cause them to sink into the fluid.  Hydrostatic pressure of the fluid pushes up on the check valve (usually a ball check) causing the valve to open and water to flow into the tube, just like water fills a drinking straw when immersed in a glass of water.  Water entering a disposable bailer will seek its own level so that a partially submerged bailer will be partially full and a fully submerged bailer will be full.  When the disposable bailer has filled to its submerged level the valve closes, preventing water from escaping.  The disposable bailer is retrieved using the tether and the sample discharged to an appropriate laboratory sample container, typically a 40ml vial (for volatile compounds) or a 1 liter glass jar (for metals analysis).

Disposable bailers fill when they sink into the water and the hydrostatic pressure of the fluid is greater outside the bailer than inside the bailer.  This pressure differential causes the check valve at the bottom of the disposable bailer to open and water to fill the bailer until the level inside the bailer reaches the level outside the bailer.  Generally, disposable bailer construction materials are lightweight (they have a low specific gravity) so that they are easy to use in the field.  The most common disposable bailer material is high density polyethylene, known for its chemical resistance, strength, and low cost.  Other materials include PVC, Teflon, and Stainless Steel.  Polyethylene has a specific gravity of just under 1.0 which means that the disposable bailers will sink until just a small portion is left floating on top of the water surface.