Cleaning systems

Mechanical Cake Removal. This method is used in the American version of the dynamic filter described under cross-flow filtration with rotating elements, where turbine-type rotors are used to limit the cake thickness at low speeds. The Exxflow filter, introduced in the United Kingdom, is described in more detail under cross-flow filtration in porous pipes. It uses, among other means, a roUer cleaning system which periodically roUs over a curtain of flexible pipes and dislodges any cake on the inside of the pipes. The cake is then flushed out of the curtain by the internal flow. 

Air cleaning systems are often used to remove dust or vapors from plant or process exhaust streams. Dust collecting systems such as filters or electrostatic precipitators that handle heavy loads of dust are usually designed to be self-cleaning, but it is stiU. necessary to enter the air cleaner periodically for inspection or repair. Dust deposits inside the equipment are likely to be stirred up and inhaled by unprotected workers. Baghouses are particularly likely to cause exposure because large amounts of dust may be retained in the cloth and released when the bags are handled. 

The latest installations incorporate a waste heat boiler in the off-gas cleaning system to recover sensible heat from the rotary kiln off-gas. There is sufficient sensible heat in the off-gas from the SL/RN process to generate 500 to 700 kWh/t of DRJ, depending on the type of reductant used. 

An air valve, sometimes called the air-activated valve, is widely used for automated food handling operations. Although electronic or electric control boxes may be a part of the system, the valve itself generally is air-activated, and is more reflable than other types. Air-operated valves are used for in-place cleaning systems, and for the transfer and flow control of various products. 

Fig. 11. Modem fermenting tank with conical bottom CIP (cleaning-in-place) = automatic cleaning system.

Coalescence The coalescence of droplets can occur whenever two or more droplets collide and remain in contact long enough for the continuous-phase film to become so thin that a hole develops and allows the liquid to become one body. A clean system with a high interfacial tension will generally coalesce quite rapidly. Particulates and polymeric films tend to accumulate at droplet surfaces and reduce the rate of coalescence. This can lead to the ouildup of a rag layer at the liquid-hquid interface in an extractor. Rapid drop breakup and rapid coalescence can significantly enhance the rate of mass transfer between phases. 

Clean systems containing acidic deposits frequently. 

Transfer system Clean system on service changes contaminated, (i.e., piping, pumps, filters, etc.) CCPS G-3 CCPS G-22 CCPS G-29... 

High efficiency, generally low pressure drop, well suited for distillation of clean systems, very low HETR... 

If a glycol pump has been operating in a clean system, no major service will probably be needed for several years. Only a yearly replacement of packing is usually required. Normally the pump will not stop pumping unless some internal part has been bent, worn, or broken. 

Fabric filters have had a long history in performing effectively in a wide variety of applications. Common applications using pulse-jet cleaning systems include ... 

Air Cleaning Systems, Inc. Sells, services and provides equipment and parts for air filtration systems. http // v m.airdeaninssystems.com... 

Aqueous and semi-aqueous cleaning systems, used for printed circuit boards and other industrial degreasing operations (Mandich and Krulik, 1992 Davis et al., 1994)... 

Cleaning systems are used to remove contaminants, clean the resulting fluid flows, and collect materials before discharge of exhaust air. 

There are many types of cleaning systems and equipment, for example ... 

Design cleaning system for contaminants, if needed e.g., it may be neces-saty to clean extract air or to recover some valuable substance (separate tree). 

Through the years many reports have been published on air recirculation. Mostly they have treated the problems in offices, living rooms, and schools. There have been many reports on air recirculation, which have concentrated on the use of some specific air cleaning system or on (XDSsible health risks. 

Typically, when central recirculation is used the contaminant in the supply air is the main source. This is not the case for industrial use, where the main source is in the ventilated room. This usually results in the concentration being somewhat higher when using recirculation than when not using it. Figure 8.1 outlines the ventilation system, the contaminant source, and the cleaning system. 

This discussion will address needs, applications, performance characteristics, and design considerations for LVHV exhaust ventilation. The applications are primarily for dust control. LVHV systems can be effective for protecting workers from dust exposures and for recovering valuable process materials. The equipment, excepting the nozzles, involves technology that is the same as for large central vacuum cleaning systems. 

Figure 10.30 illustrates a multiple-stage exhauster and smooth-flow duct (pneumatic tubing) components. It also includes pictures of air cleaner-exha uster-motor installations located outside of buildings and connected to LVHV (or central vacuum cleaning) systems inside the buildings. 

Hoffman Air Systems. High Velocity Dust Control and Central Vacuum Cleaning Systems. Bulletin A.SV-623A. New York Hoffman Air Systems, 1973. 

Electrostatic precipitation is one of the fundamental means of separating solid or liquid particles from gas streams. This technique has been utilized in numerous applications, including industrial gas-cleaning systems, air cleaning in general ventilation systems, and household room air cleaners. 

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