Sampling suction sampler used

Two other alternatives exist in sampling of coal from trucks sampling by probe, when full depth insertion and withdrawal are used, and sampling by suction sampler. The latter is a sheathed coal-drill whereby the drillings are conveyed by suction to a sample container. This method is applicable only to coarse coal and should be agreed by the interested parties. 

It is often important to quantify the contamination of pore fluid in the unsaturated soil 2one, where monitoring wells are ineffective. In this region, suction cup lysimeters are useful (7). These samplers consist of a porous cup, typically ceramic, having two access tubes which are usually Teflon. One access tube provides a pressure-vacuum, the other discharges the sampled fluid to the surface. The porous cup, typically between 2 and 5 cm in diameter, is attached to a PVC sample accumulation chamber. 

Porous cups can be used as probes in the monolith and suction can be applied to them to move water out of the soil and into a sample container under unsaturated conditions. Passive samplers that do not involve pressure or vacuum are also available [11]. 

To avoid the problems with vacuum cleaner surface dust sampling a special surface dust sampler, HVS-3, was developed (Roberts et al, 1991). The sampler consists of a nozzle that can be adjusted to a well defined distance to the surface, a cyclone that collects the dust particles, an air pump, and an exhaust filter to capture particles that are not retained in the cyclone. SVOCs may break through the cyclone as vapors and a PUF plug can be inserted after the cyclone. HVS-3 has been modified to ensure a more constant suction pressure and volume, and a known sampled area (Gyntelberg et al, 1994). The design and use of the HSV3 has now been standardized (ASTM, 1997, D 5438-94). 

Several other types of hand-held vacuum samplers have been used to collect dust from residential surfaces. One of these, the Baltimore Repair and Maintenance Study Cyclone Sampler (BRMCS) (Farfel et al 1994), has been evaluated against the HVFS. The BRMCS uses the same cyclone and catch bottle assembly as the HVS3, but a different nozzle and vacuum source. The vacuumed dust is sucked into the cyclone via a semi-rigid Tygon hose (2.54-cm o.d.) that is notched on the sampling end to simulate a nozzle. Suction is provided by a small, hand-held vacuum device (Royal Hand Vac , Model 553, 2 A). The collection efficiency for the BRMCS was determined to be 44.1 % n =6, s = 3.8) for plush uylou carpet, 61.1 % (n = 6, = 6.7) for level loop carpeting, 71.8-87.8 % n =6, s = 3.5) for upholstery and 84.7 % n = 3, s = 2.3) for wood surfaces (USEPA, 1996b). 

Low-volume air sampler A low-volume air sampler is an apparatus having a suction capacity of up to 201/min. It is used for one continuous sampling lasting from several days to 1 week. Filter papers having a diameter of 5 cm and an active-carbon cartridge can be attached as a collecting device. 

Automated samplers function without the need for an operator, giving the possibility of selection of a sampling regime arranged in dependence on time or flow-through quantity. One of these is the sampler shown in Fig. 3.66 [7]. The system has a simple battery-driven peristaltic pump, which can take samples heavily polluted with suspensions of solid material using a suction basket immersed in water. The pump feeds the sample into a 5 1 bottle at the required times determined by the timing unit. 

In certain circumstances, a suction lift sampler can be used. The samplers are portable, can be operated by hand or battery, and have pumping rates in excess of 5 gallon/minute. The major disadvantages are that they tend to degas the sample causing losses of volatiles and are limited to relatively shallow wells, less than 25 feet deep. 

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