Candle filters

Kerzen-docht, m. candle wick, -filter, n. candle filter, filter candle, -masse, /. candle composition. -nuss, /. candlenut. -nussol, n. candlenut oil. -stUrke, /. candle power, zundung,/. electric ignition,... 

A solution of 10 grams of d-glucoheptonic acid lactone in 50 ml of distilled water is warmed on a steam bath for about 2 hours to hydrolyze the lactone to the acid. The mixture is cooled and 100 ml of 95% ethanol are added. To the solution of glucoheptonic acid are added about 37 grams of erythromycin and the volume of the reaction mixture is brought to 200 ml by the addition of 95% ethanol. The reaction mixture is stirred for about 2 hours and is filtered through a porcelain filter candle of porosity 02. To provide a steriie product, aseptic technique is used throughout the remainder of the procedure. 

Preparation of Sodium 1-Methyl-5-Allyl-5-(1-Methyl-2-Pentynyl) Barbiturate A solution of 61 g of 1-methyl-5-allyl-5-(1-methyl-2-pentynyl) barbituric acid in 100 ml of ether was extracted with 465 ml of 2% aqueous sodium hydroxide solution. The aqueous extract was washed with successive 75 ml and 50 ml portions of ether. The pH of the aqueous solution was adjusted to 11.7, using 5% aqueous sodium hydroxide solution. 5 g of decolorizing carbon were added to the solution with stirring the mixture was permitted to stand for 20 minutes at room temperature, and the carbon was removed by filtration. A solution containing 4 g of sodium carbonate in 25 ml of water was added to the aqueous solution, and the mixture was filtered sterile through a porcelain filter candle of 02 porosity into sterile bottles. The aqueous solution was then dried from the frozen state, whereupon a sterile residue of sodium 1-methyl-5-allyl-5-(1-methyl-2-pentynyl) barbiturate, weighing about 62 g was obtained. 

Once filling is complete, filtration begins [Fig. 22.3(b)]. Treated brine is pumped into the vessel at the desired flow rate through an automatic control valve. The flow of brine is from the outside to inside of the filter candles. Filtrate clarity is achieved immediately no recycling of flow is required. As the filtration proceeds at constant flow, solids accumulate as a filter cake on the outside surface of the filter socks. While... 

Crystallize 2 from dry ether/dry petroleum ether at -70°C. Remove the solvent with the micro-filter candle. Recrystallise the solid under the same conditions. 

Originally a hot gas filter of the ceramic type was installed. This filter consisted of ceramic filter candles arranged in six groups with separate back-pulsing. 

During the summer 1998 it was decided to install metal filter candles instead of the ceramic candles in the main hot gas filter. The metal filter candles are installed in the original filter vessels but with a new tube sheet and back-pulsing arrangement. 

Tuhtdar Presses As the name implies, this press is composed of a candle filter inside a cyhndrical hydrauhc casing (Fig. 18-192). The filter cloth is wrapped around the filter candle, and a diaphragm is attached to the inner side of the outer casing. During the filtration step, the space in between two cylinders is filled with slurry, and pressure filtration is conducted. At the end of the filtration step, the diaphragm is inflated to squeeze the cake around the filter candle. At the end of expression, the bottom of the hydrauhc casing tube is opened and the filter assembly is lowered. Air is then introduced to pulse the cake off the candle. Alter the cake is discharged, the inner filter candle moves back, and the bottom is closed for the next filtration cycle. 

Membrane processes are used to filter liquids. Instead of conventional filter materials (e.g. filter cloth, filter candles,) microporous membranes are employed with molecular size pores. First the industry had to learn how to manufacture membranes with controlled pore sizes. To optimise the filtration capacities specific filter structures had to be designed in which the liquid followed well defined flow patterns on one side of the membrane. Many different systems were developed for the varied applications, all having their advantages and also disadvantages, i.e. plate modules, tubular modules, spiral wound membranes, etc. Research and development in this field is far from being exhausted. Today membrane systems are available which are sufficiently resistant to chemical, mechanical and thermal stress. They are produced from plastic... 

Candle FilterS Tubular filter elements contained in a matching vessel are known as candle filters. The actual filter vessel may contain one or more filter candles, and may be used as pressure or suction filters for the filtration of liquids and gases. A particular advantage offered is that candles may readily be changed to different types, to suit particular requirements or applications. A typical candle filter is shown in Fig. 11. Materials of candles are selected to fit a particular process. 

Pressure filters are usually operated batch-wise. The batch pressure filters can be classified as tank (pressure vessel) filters or presses. Tank filters have filter elements of different types mounted in pressure vessels. Tank filters are divided into pressure nutsches, leaf filters, candle or tubular filters, bag filters, and cartridge filters. Presses (see Figure 22.38) consist of a series of filter surfaces (plates). The elements are mounted on a frame and are pressed together mechanically. 

Sintered glass funnel, seitz filter, or filter candle... 

Commission of the European Communities Directorate-General for Energy Demonstration of Hot-Gas Cleaning with Hanging and Upright Ceramic Filter Candles , Final technical report, Phase II, SF/3001/93, Berlin, Germany, 2002. 

The frit valves may be opened even when there is a considerable pressure difference between the two sides of the valve. The frits, which are impermeable to I, thus replace the rising floats (Fig. 31 b). They have the disadvantage of offering considerable resistance to the gas flow. A modification of the frit valve, described by Wiberg (see also the original model with filter candle by A. Stock tl]),is also commercially available. Its fimctioning may be readily seen from Fig. 31 c. The gas should flow from the top to the bottom. 

It is economically attractive to provide as many candles as possible inside a single pressure vessel. This will provide the greatest filtration area and hence product flow rate. However, one factor which considerably affects the ease of cake discharge is the occurrence of bridging between the filter candles. If no space exists for the cake to break... 

In tubular qtplications, Figure 11.52, successful appHcations include those designs vtbich ensure adequate cake discharge frciMes. The filter candle shown allovys e q)ansion of the... 

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