Closed loop system cleaning

Closed loop system (cleaning) A cleaning line where the cleaners and rinsing agents are recycled so that there is very little dilute liquid waste generated. Contaminants are in the form of solids on filters or concentrated liquid wastes. See also Enclosed system. 

Typically, the level of glycol required in a HW heating system is only 15 to 25% v/v or so (less than the 35 15% usually employed in cold and chilled-water closed-loop systems). Where glycols are added, the system must be cleaned and flushed first. The system can be partly drained to accommodate the volume of 100% glycol required or alternatively filled with a prediluted mix. If a 20% v/v strength is required, 25% v/v should be specified to allow for inaccuracies in mixing. 

An example of such a closed-loop system might include a closed solvent recovery system in which the dirty solvents are piped from the degreasing unit to a solvent still where the solvent is cleaned, and then piped back to the degreasing unit. 

In this section, we will derive the closed-loop transfer functions for a few simple cases. The scope is limited by how much sense we can make out of the algebra. Nevertheless, the steps that we go through are necessary to learn how to set up problems properly. The analysis also helps us to better understand why a system may have a faster response, why a system may become underdamped, and when there is an offset. When the algebra is clean enough, we can also make observations as to how controller settings may affect the closed-loop system response. The results generally reaffirm the qualitative statements that we ve made concerning the characteristics of different controllers. 

Throughout the process, water, surfactant, and NAPL are recovered (as much as possible) for reuse and/or recycling. Many of the aboveground leaching facilities are essentially closed-loop systems. In most cases, the resulting clean soil can be used for backfill, landscaping, or similar purposes. 

Use closed-loop systems, which might be installed down-mine , or within settlement basins at a minewater treatment plant. Here the collector fluid circulates in a closed-loop and never comes into contact with the mine water. Likewise, mine water never enters the heat pump or heat exchanger elements. The problem is thus wholly averted, although there are limitations in capacity to closed-loop systems. For larger capacity operations, open systems will be preferred. Furthermore, the exterior of such closed-loop systems may become heavily fouled, necessitating periodic removal for cleaning. 

Precommission Cleaning of Closed-Loop Systems to Include Fast-Track HVAC Projects)... 

Some information on the cleaning stages of closed-loop systems is presented in the following sections. 

As with cleaning closed-loop systems, it is always necessary to first identify the basic types of foulants and problems likely to be found in any new open cooling system and to then select both an appropriate chemical treatment and a cleaning process. 

Nevertheless, there are still some cooling systems (especially closed-loop systems) that do not receive any form of chemical inhibitor dosing or other treatment. This situation typically persists because the operator either remains uneducated or skeptical concerning the benefits and cost-effectiveness of water treatment or relies on low-cost labor to provide regular manual cleaning. 

Many closed-loop hot/cold/chilled water systems are not treated, perhaps due to the mistaken notion that treatment is not required. Only when severe corrosion and fouling/blockages problems occur is something done, by which time it is normally too late to fully recover the situation. Closed-loop systems should always be cleaned, passivated, and treated. Treatment is most usually applied by means of a dosing pot (bypass feeder) installed on a bypass line. Some operators also install sidestream filters to remove suspended iron oxide. This is most probably not necessary if the... 

Clean, segregated plastics arising from industrial operations (including the ultimate disposal of motor car components) should be recycled in a closed loop system into the primary application. Some packaging, notably film wrap, that can be easily collected in bulk from industrial waste may be economically resourced in the same way. Clean PVC waste can be effectively reprocessed in this way provided the nature of the plasticiser/stabiliser formulation is known. This will be discussed in detail in the following sections. 

Starting in December 1984, the 107-N spent fuel storage basin cooling water recirculation system was operated. The 107-N basin recirculation facility cleaned N Basin in a closed-loop system. Mixed wastes were routed to the 190,000-L (50,000-gal) tank, where they were neutralized and then pumped to the 1314-N LWLS (DOE-RL 1990). 

Enclosed system (cleaning) Cleaning, rinsing, and drying systems where the liquids are contained and the vapors are condensed and recycled. This reduces pollution generation. Examples Vapor cleaners spray cleaners vapor dryers. See also Closed-loop system. 

CAS 111-30-8 8001-54-5 EINECS/ELINCS 203-856-5 204479-9 Uses Microbicide, slimicide, bactericide, algicide, surfactant for water treatment, recirculating cooling towers, air washer systems, recirculating process water, closed loop systems, reverse osmosis, to clean and penetrate microbiologically fouled surfe. 

SafeChem, a subsidiary of Dow, has developed a handling system for chlorinated solvents that allows them to be used in closed-loop degreasing systems. The Safe-Tainer system uses two dedicated double wall containers one to hold fresh solvent and the other used solvent. The containers are connected to the cleaning equipment with zero dead volume, leak-free connections that prevent spills, leaks or vapour emissions during use. Used solvent is collected for recycling and professional disposal of any residues. The system minimises solvent use and release to the environment. A study carried out by Dow during a trial in... 

Water is one of the most widely used raw materials in the manufacture of aqueous paint formulations. But as well as being used in production it can have a number of other uses, e.g. cooling and cleaning. Because of the cost of "new" water and disposal of contaminated water most manufactures have introduced closed loop or recycling systems. 

Outside of the occasional system calibration and model verification tests, the routine maintenance burden of a Raman system is quite low. Optical windows may need to be cleaned, though automatic window cleaning systems can be implemented if it is a known issue. The most likely maintenance activity is laser replacement. Some systems have a backup laser that turns on automatically if the primary laser fails. This lessens the impact of a failure if the unit is being used for closed-loop process control. With a quality instrument and well-developed models, process Raman installations need less maintenance than many competing techniques. 

As an option, the system can be supplied as a closed loop for connecting and recycling the cleaning fluid. Such a system would include a collection tank and a filter system. 

Similar plants have been designed to clean and separate PCW that enters the closed-loop recycling system, hence materials from specific domains of application, e.g., automotive or agricultural. In the latter case, scrap plastics film, composed mostly of PE and PVC, is also shredded, washed, and segregated by the floatation method [Anonym., 1991]. 

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