Sand washer

Dyna Sand Filter. A filter that avoids batch backwashing for cleaning, the Dyna Sand Filter is available from Parkson Corporation. The bed is continuously cleaned and regenerated by recycling solids internally through an air-lift pipe and a sand washer. Thus a constant pressure drop is maintained across the bed, and the need for parallel fdters to low continued on-stream operation, as with conventional designs, is avoided. 

Now, to convert a run-of-bank stock sand into a usable sand, an experimental curve such as Figure 7.9 is entered to determine the size of separation corresponding to p4 and ps- Having determined these sizes, the stock sand is washed in a sand washer that rejects the unwanted sand. The washer is essentially an upflow settling... 

In the early development of filters, units that had been clogged were renewed by scraping the topmost layers of sand. The scraped sands were then cleaned by sand washers. In the nineteenth century, studies to clean the sand in place, rather than taking out of the unit, led to the development of the rapid-sand filter. The method of cleaning is called backwashing. 

A deep bed system that avoids hetch backwashing to clean the filter is lhe Dyan Sand" filler. The bed design is continuously claimed and regenerated by the internal recycling of solids from the bottom of the bed to the top through an air-lift pipe and a sand washer. This filter allows a constant pressure drop across the bed and avoids the need for a parallel filter to allow backwashing. 

Similar applications to log washer, but lighter action. Tumbling (85% critical speed) provides attrition to remove clay from sand. Also removes trash. 

Drill aN the washers out to an 10 of 37ff" and sand all galvanizing off of them (be sure to degrease with alcohol before soldering). ... 

Fig. 19 Automatic backwash sand filter (Centra-flo ) 1, Overflow 2, Alter influent 3, coarse media 4, fine media 5, filtrate nozzles 6, filtrate chamber 7, level controller 8, filter reject 9, washbox 10, counter-current washer 11, airlift 12, central feed chamber. (View this art in color at www. dekker.com.)...

This is a spectrum of the same washer but it has been sanded to remove some of the zinc surface coating. 

Figure 8.51 Qualitative EDXRF spectrum of a zinc-coated iron washer, (a) The ooated washer. The peaks present are, from left to right, Fe K , Fe Kp, Zn K , and Zn Kp. (Confirm these peaks by looking in Table 8.A.2.) (b) The same washer, but after sanding to remove some of the surfaoe. Note the decrease in the intensity of the Zn peaks and the increase in the Fe peaks. These spectra were collected for 50 s with an Rh tube at 30 kV and 0.01 mA, under vaouum, using a filter to remove the X-ray tube lines. ( Thermo Fisher Scientific, www.thermofisher.com. Used with permission.)...

The potatoes must be thoroughly washed to remove all mud, dirt, and sand. Potatoes are often washed in machines fitted with cylinder brushes or studded rubber rolls that vigorously scrub the potatoes as they are tumbled and sprayed with water. Washing also assists in sprout removal. Equipment using large amounts of water for washing is now a concern to processors because of the need to recycle the water to meet required water pollution controls. Generally, brush washers use much less water than barrel washers or deepwater washers. 

The flow cell was designed to make optimum use of the cavity and to monitor the temperature of the flow cell directly using an inbuilt IR sensor. To this end, a standard pressure rated glass tube (10 luL) is fitted with a custom built steel head and it was filled with sand (10 g) between two drilled porous frits. This is to minimize dispersion and effectively create a lattice of microchannels. It is charged with solvent (5 mL volume), sealed using polytetrafiuoroethylene (PTFE) washers and connected to an HPLC flow system with a backpressure regulator. 

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