Fogging systems

Automatic fogging systems are available to disinfect rooms. A dense fog is quickly achieved by atomising disinfectant solution through nozzles. 

Production equipment that cannot be sterilized must be sanitized and disinfected by an appropriate method. This can be done by use of biocides like alcohols (70%), hydrogen peroxide, or formaldehyde-based chemicals or a combination of these. These can either be used for surface disinfections by wiping or spraying or even better by use of gas or dry fog systems for application of the disinfectants. The effect of cleaning and sanitation should be monitored. Microbiological media contact plates can be used to test critical surfaces, as inside the hot cells or glove boxes. The test samples must then be handled and monitored as radioactive contaminated units. 

These few examples show how the use of nanocomposite systems with hetero polysiloxane type of matrices leads to interesting properties for applications. Further developments using these basic systems are transparent controlled release coatings for anti-fogging systems [41], anti-corrosive systems for metal protection [42], and nanocomposite optical bulk materials [43],... 

One of the special imaging procedures which have been successfully used to study fineparticle systems is far-field holography. The basic system of this technique is illustrated in Figure 2.27. In the example shown the technique was used to size fog droplets. The laser beam was shone through the fog system and light scattered from the droplets interacted with the forward traveling beam to produce the holographic record... 

Effective building envelope and air handling designs took comfort most of the way from theory to reality in ISU s Hach Hall. An existing in-house deionized water supply and a new fogging system finished the task and saved an estimated 22% in humidification costs. 

Iowa State University s (ISU) new Hach HaU is an exception. Opened in the fall of 2010, the 52 million research facility incorporates numerous features to reduce its environmental footprint including rainwater capture, separation of laboratory spaces from classrooms, and the use of a fogging system for humidification, rather than a traditional boiler. 

To achieve a design relative humidity of 30%, the humidification system needs to operate about 3,500 hrs/yr. Not all of this is at full capacity the full load humidifier s hours per year were calculated at 1,767. For the 200 hrs/yr the ambient temperatures were below zero, 4,600 to 4,800 lbs water/hr are required for the four main AHUs. As outside temperatures rose, the need for humidity gradually drops until, at 45°, the humidity load is only 740 Ibs/hr. To provide the humidity in the most efficient manner, ISU decided to use a high-pressure fogging system. 

At 1 per 100 cu ft (CCF) this would cost 136,770 per year. A high-pressure fogging system from Mee Industries Inc. (Irwindale, CA) sized to produce 4,800 lbs of humidity/hr, would use 10 kW, or 17,670 kWh/yr. At an electricity price of 0.065/kWh, the total price would be a projected l,149/yr. However, because the fogging system would lower the air temperature, requiring additional heat input, the total cost comes to 106,703/yr, or about 30,000 less in energy costs than using a gas boiler. 

The fogging system, like the rest of the H VAC system, is tied into the campus s Johnson Controls Metasys BAS. Depending on the need for humidity in one of the quadrants, the appropriate number of solenoid valves open up, allowing the water to flow through a series of 0.75- and 0.50-in. stainless steel pipes to the nozzle arrays in the air handler. Each of the arrays consists of nine 0.50-in. lines with a total of 94 fogging nozzles. 

In the case of a combustible gas s, the ignition results in a flame (combustion wave) propagation through the mixture, and the cloud of micro-droplets acts as a volumetric-surface inhibitor due to the heat loss by the droplet evaporation at the flame front. However, the partial condensation caused by the sudden expansion of the combustible mixture + water fog system near the combustion limit creates preconditions for transforming the incombustible system into a combustible one. It is a situation where the role of the fog droplets in flame expansion is crucial. 

Measurement of Turbulent Combustion Suppression Efficiency in Hydrogen + Air + Water Fog System... 

Modem NDT film systems (with Pb screens) are very linear X-ray detectors. This is shown in fig.l for different NDT film systems and a X-ray tube at 160 kV. Note that for histoncal reasons the film response curve is often plotted as film density versus log (radiation dose), which hides this linear relationship. The film density is the difference between the measured optical film density and the fog density Db of the film base. 

Laser communication systems based on free-space propagation through the atmosphere suffer drawbacks because of factors like atmospheric turbulence and attenuation by rain, snow, haze, or fog. Nevertheless, free-space laser communication systems were developed for many appHcations (89—91). They employ separate components, such as lasers, modulators, collimators, and detectors. Some of the most promising appHcations are for space communications, because the problems of turbulence and opacity in the atmosphere are absent. 

Cooling-Tower Plumes. An important consideration in the acceptabiHty of either a mechanical-draft or a natural-draft tower cooling system is the effect on the environment. The plume emitted by a cooling tower is seen by the surrounding community and can lead to trouble if it is a source of severe ground fog under some atmospheric conditions. The natural-draft tower is much less likely to produce fogging than is the mechanical-draft tower. Nonetheless, it is desirable to devise techniques for predicting plume trajectory and attenuation. 

An ion chromatographic system that included column switching and gradient analysis was used for the deterrnination of cations such as Na", Ca ", Mg ", K", and NH" 4 and anions such as Cf, NO, NO , and in fog water samples (72). Ion-exchange chromatography compares very well with... 

A good sensitizing dye does not interfere with other system properties. Sensitizing dyes can sometimes influence the intrinsic response of a chemically sensitized emulsion, leading to desensitization or additional sensitization. The dye can also interfere with development rate, increase or decrease unwanted fog density, and remain as unwanted stain in the film after processing. The dye should have adequate solubihty for addition to the emulsion, but should not wander between layers in the final coating. 

Oil mist systems exist to provide eontinuous minute quantities of oil fog to the rolling assembly. These systems normally employ an additional pump, atomizer, and filter. These systems are gaining popularity in hot applieations, or with heaty thrust and radial loading. The oil fog is sprayed into the bearing ehamber with either a wet sump or a dry sump. The wet sump method provides the bearings with a bath (the liquiei oil level) and a fog spray. See Figure 11-1. 

Evaporative methods-direct water fogging Refrigerated inlet cooling systems-ical refrigeration... 

Depending on the specifics of the project, location, climatic conditions, engine type, and economic factors, a hybrid system utilizing a combination of the above technologies may be the best. The possibility of using fogging... 

In recapping, DAF is the process of removing suspended solids, oils and other contaminants via the use of bubble flotation. Air is dissolved into the water, then mixed with the wastestream and released from solution while in intimate contact with the contaminants. Air bubbles form, saturated with air, mix with the wastewater influent and are injected into the DAF separation chamber. The dissolved air then comes out of solution, producing literally millions of microscopic bubbles. These bubbles attach themselves to the particulate matter and float then to the surface where they are mechanically skimmed and removed from the tank. Most systems are versatile enough to remove not only finely divided suspended solids, but fats, oils and grease (FOG). Typical wastes handled include various suspended... 

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