Cloth filter

Eor evaluation of flocculants for pressure belt filters, both laboratory-scale filters and filter simulators are available (52,53) in many cases from the manufacturers of the full-scale equipment. The former can be mn either batchwise or continuously the simulators require less substrate and are mn batchwise. The observed parameters include cake moisture, free drainage, release of the cake from the filter cloth, filter blinding, and retention of the flocculated material during appHcation of pressure. 

What is the % open area of the weave of a cloth filter, where the opening is on the average 50 microns and the thread diameter is 85 mills. 

Select a cloth filter for a filter press application in which the water is both alkaline and has a high content of solvents. The operating temperature could reach as high as 200° F on excursions. 

Cloth-filter collectors A mechanical method of filtration of particulate matter from a gas stream by the use of a number of doth bags. Its operation is similar to a vacuum cleaner method of removal. 

Filter aids are widely used in die fermentation industry to improve the efficiency of filtration. It is a pre-coated filter medium to prevent blockage or blinding of the filter by solids, which would otherwise wedge diemselves into the pores of the cloth. Filter aid can be added to the fermentation broth to increase the porosity of the cake as it formed. This is only recommended when fermentation product is extracellular. Filter aid adds to the cost of filtration. The minimum quantity needed to achieve the desired result must be established experimentally. Fermentation broths can be pretreated to improve filtration characteristics. Heating to denature proteins enhances the filterability of mycelial broths such as in penicillin production. Alternatively, electrolytes may be added to promote coagulation of colloids into larger, denser particles, which are easier to filter. The filtration process is affected by the viscosity and composition of the broth, and the cell cake.5... 

This type of filter can be used for removal of Penicillium and Streptomyces mycelia in the production of penicillin and streptomycin, respectively.5 In these processes the rotary drum filter is used with a pre-coated cloth filter with filter aid the filter cake is removed by a knife blade which scrapes the cake from the rotating drum. 

Figure 16-2 A cloth filter. The dirty air enters in the side near the bottom as shown in the figure on the left. The large particles drop to the bottom. The small particles are carried upward and deposited on the exterior surface of bag (shown in black).The air passesthrough the bag and exits through the exhaust plenum. The bags are cleaned periodically, but only a few at a time. When this occurs the exhaust plenum is closed as shown in the figure on the right. A burst of air is admitted to the inside of the bags this knocks the small particles off the sides and they settle to the bottom where they are discharged through a rotary valve. Courtesy of the Dustex Division of American Precision Industries, Inc.

The mixture is then run on to a sheeting table which is made on the same principle as a paper-making machine, but with the wire replaced for safety by a suitable cloth filter. The pulp passes over suction tubes and between rollers in order to remove as much water as possible, so that the paste when stripped from the cloth contains 20-25% of water. It is dried on trays or else in trucks through which air at 50°C is blown. 

FILTER UR LOGICAL DISP W/CLOTH FILTER AND TAB GRIPS 1000S 6515012106172 PG 101,91 ... 

Fig. 6. Sketch of boiler (K-3A) system at the Eesti power plant, showing locations of ash sampling. Samples from locations 10 and 11 were taken from the Balti power plant (modified from Paat Traksmaa 2002, fig. 1, p. 374). Furnace bottom (1) gas duct superheater (2), economizer (3), cyclone (4), electrostatic precipitators (ESP) prechamber (5), field I (6), field II (7), field III (8), field IV (9), flue cyclone (10) and cloth filter (11). ( " Oil Shale.)...

During the granulation or drying process, cloth filters are mechanically shaken to dislodge any product which adhered while cartridge filters use a low pressure compressed air blowback system to do the same. 

One of the earliest descriptions of the manufacture of mercury fulminate given by Chevalier [59] is as follows 300 g of mercury are dissolved in 3000 g of cold nitric acid (54% HN03, s.g. 1.34) and the solution is poured into a flask containing 1900 g of 90% alcohol. After few minutes a vigorous reaction begins and crystals are precipitated. On completion of the reaction 238 g and 158 g of alcohol are added in turn. The fulminate is filtered off through a cloth filter and carefully washed free of acid with water. The yield is 118-128 parts of fulminate per 100 parts of mercury, i.e. 83-90% of theoretical. 

The fulminate is precipitated in the form of greyish needles. When the reaction is complete, the reactor is allowed to stand for approximately 30 min while the contents are cooled. 1-2 1. of water are then poured in and the liquid is decanted from above the precipitated crystals. The precipitate is transferred to a cloth filter and washed with distilled water until completely free of acid. The product is then screened on a silk sieve (approximately 100 mesh/cm2) which retains the larger crystals. The smaller crystals are collected for direct use. The large ones are ground under water, passed through the same sieve and added to the previous batch. 125 parts of fulminate are obtainable from 100 parts of mercury, which corresponds to a yield of 88%. 

The lead picrate for this purpose was produced in the following way [42]. Into a stainless-steel reactor equipped with a stirrer of the type used for the manufacture of lead azide and other initiators (cf. Fig. 49) 8 1. of a solution containing 1.44 kg of lead nitrate and 151. of ice water were poured. Fifteen litres of a solution containing 1.5 kg of picric acid were then added. During the reaction the temperature should be maintained between 6 and 10°C. Since the temperature rises with the precipitation of lead picrate, 7-8 more litres of ice water must be poured into the reactor, usually a few minutes after the picrate has begun to precipitate. After 4 hr the liquid was decanted from above the precipitate the latter was transferred to a cloth filter and washed with alcohol (101.) to which an aqueous solution of lead, nitrate (500 ml of a 30% solution) has been added to avoid the dissolution of lead picrate during washing. 2.2 kg of product was obtainable from one batch. 

From the magnesium styphnate solution so prepared, 86.4 1. of liquid was decanted, leaving the lower layer in which the sediment was collected. This solution was heated to 60°C, while stirring, and 22.71. of 34% solution of lead nitrate, s.g. 1.274 (31°Be) was then poured into it during a period of 20-30 min, while stirring continued and the temperature was maintained at 60°C. When the solutions were mixed, the contents of the reactor were cooled as quickly as possible to 25°C when this temperature has been reached the stirrer was stopped and the precipitated sediment of lead styphnate was allowed to settle. The liquid from above the sediment Was then decanted, and the latter was first washed out of the reactor by a stream of water, and transferred onto a cloth filter, where it was washed again as is the custom with other primary explosives. From the above mentioned amounts of raw material about 8 kg of lead azide was obtained. 

Vacuum filtration is also common in metal finishing industries. A vacuum in this method helps to draw the sludge through filter media. Nylon or polypropylene cloth filter materials are used with fairly good results, although the best filtration is achieved when the filter belts are coated with diatomaceous earth (DE) or with paper. Sludges with 20 to 35% solids content can be produced through this method. 

Comparison of Molecular Sieve and Ketone Dewaxing. To serve as a basis for comparison, a sample of the C16-C32 wax distillate was dewaxed using conventional procedures. The oil feed was dissolved in ketone solvent and cooled at a rate of 1.3 K per minute with stirring to 260 K. The slurry was filtered with a 20-35 pm cloth filter and the cake was washed with additional solvent to... 

A wide variety of filters are available for the cell recovery. There are generally two major types of filters pressure and vacuum filters. The detailed descriptions of those filter units can be found in Chemical Engineers Handbook (Perry and Chilton, 1973). The two types of filters most used for cell recovery are the filter press and rotary drum filters. A filter press is often employed for the small-scale separation of bacteria and fungi from broths. For large-scale filtration, rotary drum filters are usually used. A common filter medium is the cloth filter made of canvas, wool, synthetic fabrics, metal, or glass fiber. 

Flutriation methods can be used successfully with sub-sieve sizes and for particles which arc. not much below 1 n in diameter. The effectiveness of elutriation is determined by the type of filter used to capture the dust. Smaller particles could undoubtedly be obtained if an electrical precipitator, instead of cloth filters, were used for the dust passing the elutriation cylinder. 

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