High pressure filters

High pressure filter blow-off system. Oust adhering to the filters is Mown off continuously with compressed air whereby fluidizing is not interrupted. 

Preparation of NOAC, ara-C-NOAC, 5-FdU-NOAC and ETC-NOAC Liposomes by High Pressure Filter Extrusion... 

Liposomes belong to the most studied particulate carrier systems. In the past decades, a vast number of liposome preparation methods for the encapsulation of a large variety of molecules have been developed and refined. We refer to the corresponding literamre and to our publications for more information. We recommend the high pressure filter extrusion method for the preparation of peptide or DNA containing liposomes because of its ease, versatility, up-scaling options and high quality of the liposomes produced. 

Liposome Preparation by High Pressure Filter Extrusion... 

Key words Phos phoHpid gel. Sustained drug release. High-pressure homogenization. High-pressure filter extrusion. Passive loading... 

Figure 37-24. A high pressure filtering arrangement. (Courtesy - Gelman Sciences, Ann Arbor, MI)...

TyriL [Dow Plastics] SAN resin thermoplastic for inj. and blow mohfog, cosmetic containers, industrial battery cases and caps, high-pressure filter housings, appUanoes, blood aspi-rators, otto medi parts, conneaors, tumblers, dinnerwaie, utensils. 

In-line High-Pressure Filter assembly Figure 10.400 In-line high-pressure filter schematic and filter assembly. 

Propane deoiling is accomplished using high pressure filters that are required to handle die higher temperatures that must be used to melt the softwax. The finished wax produced from deoiling is a valuable by-product and margins may at times exceed dewaxed oil margins. 

The placement of a 0.5 micron high-pressure filter between the injector and column offers important protection of the latter. It is important to monitor the system pressure... 

In a broad sense, hydraulic filters may be described as high pressure, medium pressure and low pressure filters. High pressure filters will operate in excess of 400 bar working pressure, with flows of 4501/min (although some operate to more than 1000 bar and for flows up to 10001/min). They can be manifold mounted and include both single and duplex housings. 

The high-pressure water supply service is employed for the operation of the ordinary filter pump, which finds so many applications in the laboratory. A typical all metal filter pump is illustrated in Fig. 11, 21, 1. It is an advantage to have a non-return valve fitted in the side arm to prevent sucking back if the water is turned off or if the water pressure is suddenly reduced. Theoretically, an efficient filter pump should reduce the pressure in a system to a value equal to the vapour pressure of the water at the temperature of the water of the supply mains. In practice this pressure is rarely attained (it is usually 4 10 mm. higher) because of the leakage of air into the apparatus and the higher temperature of the laboratory. The vapour pressures of water at 5°, 10°, 15°, 20° and 25° are respectively 6-5, 9-2,12-8, 17 5 and 23 8 mm. respectively. It is evident that the vacuum obtained with a water pump will vary considerably with the temperature of the water and therefore with the season of the year in any case a really good vacuum cannot be produced by a filter pump. 

Dewatering of high value products and particle systems sensitive to high pressure drops are the most likely candidates for electrofiltration. The Dorr-OHver Electrofilter is a commercial example of a vacuum filter adapted for electrofiltration. 

The most important feature of the pressure filters which use hydrauHc pressure to drive the process is that they can generate a pressure drop across the medium of more than 1 x 10 Pa which is the theoretical limit of vacuum filters. While the use of a high pressure drop is often advantageous, lea ding to higher outputs, drier cakes, or greater clarity of the overflow, this is not necessarily the case. Eor compressible cakes, an increase in pressure drop leads to a decrease in permeabiUty of the cake and hence to a lower filtration rate relative to a given pressure drop. 

This reduction in permeabiUty due to cake consoHdation or coUapse may be so large that it may nullify or even overtake the advantage of using high pressures in the first place and there is then no reason for using the generally more expensive pressure filtration hardware. While a simple Hquid pump may be cheaper than the vacuum pump needed with vacuum filters, if air displacement dewatering is to foUow filtration in pressure filters, an air compressor has to be used and is expensive. 

An important variation of this filter is based on replacing the rigid outer waU necessary for containing the feed and the cake on the rotating table by an endless mbber belt. The belt is held under tension and rotates with the table. It is in contact with the table rim except for the sector where the discharge screw is positioned, and where the belt is deflected away from the table to aUow the soHds to be pushed off the table. The cloth can also be washed in this section by high pressure water sprays. This filter, recendy developed in Belgium, is avaUable in sizes up to 250 m, operated at speeds of 2 minutes per revolution, and cake thicknesses up to 200 mm. 

In conventional disk filters, cake discharge is usually performed by a scraper blade, for cakes thicker than 10 mm, or sometimes by a tapered roU air blowback is often used to assist the discharge. High pressure sprays also have been used for cake discharge. 

A continuous pressure filter may be defined as a filter that operates at pressure drops greater than 100 kPa and does not require intermption of its operation to discharge the cake the cake discharge itself, however, does not have to be continuous. There is Htfle or no downtime involved, and the dry soHds rates can sometimes be as high as 1750 kg/m h with continuous pressure filters. 

Despite the disadvantages, the advantages of high throughputs and low moisture contents in the filtration cakes have justified the vigorous development of continuous pressure filters. 

There are many technical problems to be considered when developing a new commercial and viable filter. However, the filtration hardware in itself is not enough, as the control of a continuous pressure filter is much more difficult than that of its equivalents in vacuum filtration the necessary development may also include an automatic, computerized control system. This moves pressure filtration from low to medium or even high technology. Disk Filters. 

Thickening Pressure Filters. The most important disadvantage of conventional cake filtration is the declining rate due to the increased pressure drop caused by the growth of the cake on the filter medium. A high flow rate of Hquid through the medium can be maintained if Httle or no cake is allowed to form on the medium. This leads to thickening of the slurry on the upstream part of the medium filters based on this principle are sometimes called filter thickeners. 

Od condensed from the released volatdes from the second stage is filtered and catalyticady hydrotreated at high pressure to produce a synthetic cmde od. Medium heat-content gas produced after the removal of H2S and CO2 is suitable as clean fuel. The pyrolysis gas produced, however, is insufficient to provide the fuel requirement for the total plant. Residual char, 50—60% of the feed coal, has a heating value and sulfur content about the same as feed coal, and its utilisation may thus largely dictate process utdity. 

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