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Dew condensing

Humidity sensors consist of two major types, i.e., one which measures relative humidity and the other which detects dew condensation. The sensors for relative humidity made of ceramic or organic polymers are produced in amounts exceeding one million. They are applied to controling systems in air conditioning, micro wave ovens, and so on... [Pg.43]

Dew condensation sensors are usually made of hydrophilic or swelling organic polymers in which carbon particles are dispersed... [Pg.43]

This type of sensor utilizes a drastic increase in resistance at the point of dew condensation, since water absorption swells the polymers to counteract ohmic contact between carbon particles. This type sensor is now widely applied to humidity controling systems of video tape recorders or car windows. [Pg.43]

Beyond these differences in rainfall, most areas of the United States, excepting desert areas, have frequent dew condensation at night. In Florida, which is probably the extreme, dew presence ranges from 2 hr in the dry winter to 12 hr in the wet summer. In extensive and repeated studies of organo-phosphate insecticides and their oxon metabolites in Florida... [Pg.68]

Which of the following changes can be reversed by changing the temperature (that is, which are physical changes) (a) dew condensing on a leaf (b) an egg turning hard when it is boiled ... [Pg.27]

Inside each solar collector two types of dew (condensation) points exist. One is a moisture dew point and the other a series of dew points resulting from organic compounds. The amount of a given vapor present in the air at any specific temperature/ pressure condition is essentially a function of Its relative volatility and its thermodynamic activity. [Pg.81]

Put the grid into a holder placed in a cryochamber. Do not remove the grid from the cryochamber to prevent dew condensation. [Pg.326]

Insert the cryohoider into the microscope immediately. The transfer time should be minimized to prevent dew condensation. [Pg.326]

The amount of water on a surface covered by dew is approximately 10 g/m, which is considerably more than on surfaces covered by adsorption layers. In heavily polluted areas dew pH values of 3 or lower have been found on inert substrates such as painted roofs, where dry deposition between periods of rain have led to the accumulation of corrosive, fairly acid pollutants. Concentrations of 0.35 g/L of chlorides and 0.20 g/L of sulfates have been reported. These values are approximately 100 times higher than those formed in rainwater at the same location. This extreme corrosivity formed by dew condensation may be seen in the effect of run-off of condensed water from painted roofs. Such run-off may cause perforation of gutters of galvanized steel plate within 3 years. [Pg.8]

Hydrophobic Surfaces Made Hydrophilic. Greenhouses are often covered with transparent plastic sheets. Morning dew condensing into fine droplets on the plastic scatters the light and robs flowers and plants of much needed sunlight. It is desirable to find a way to force water to spread into a continuous film, in other words, to Svet the material. There are plasma treatments that can create hydrophilic groups on the surface of the plastic, thereby lowering 7c-... [Pg.24]

The most important factor in atmospheric corrosion, overriding the presence of any other surface contamination, is moisture, either in the form of rain, dew, condensation, or high relative humidity (RH). [Pg.334]

Dew condensation on the surface of substrates before bonding is another problem. The dews can corrode the surface before bonding and inhibit adhesive tack. Just after the start of room heating in winter, cold members may cause dews on their surfaces. Therefore, humidity control is also necessary in this situation. [Pg.1039]

Similarly, for a dew-point calculation (incipient condensation) a is 1 (again Q = 0) and Equation (7-13) leads to... [Pg.114]

Both the reboiling and condensing processes normally take place over a range of temperature. Practical considerations, however, usually dictate that the heat to the reboiler must be supplied at a temperature above the dew point of the vapor leaving the reboiler and that the heat removed in the condenser must be removed at a temperature lower than the bubble point of the liquid. Hence, in preliminary design at least, both reboiling and condensing can be assumed to take place at constant temperatures. ... [Pg.341]

The initial temperature of a gas condensate lies between the critical temperature and the cricondotherm. The fluid therefore exists at initial conditions in the reservoir as a gas, but on pressure depletion the dew point line is reached, at which point liquids condense in the reservoir. As can be seen from Figure 5.22, the volume percentage of liquids is low, typically insufficient for the saturation of the liquid in the pore space to reach the critical saturation beyond which the liquid phase becomes mobile. These... [Pg.102]

Gas is produced to surface separators which are used to extract the heavier ends of the mixture (typically the components). The dry gas is then compressed and reinjected into the reservoir to maintain the pressure above the dew point. As the recycling progresses the reservoir composition becomes leaner (less heavy components), until eventually it is not economic to separate and compress the dry gas, at which point the reservoir pressure is blown down as for a wet gas reservoir. The sales profile for a recycling scheme consists of early sales of condensate liquids and delayed sale of gas. An alternative method of keeping the reservoir above the dew point but avoiding the deferred gas sales is by water injection. [Pg.103]

The diagram (Fig. 5.21) shows that as the pressure is reduced below the dew point, the volume of liquid in the two phase mixture initially increases. This contradicts the common observation of the fraction of liquids in a volatile mixture reducing as the pressure is dropped (vaporisation), and explains why the fluids are sometimes referred to as retrograde gas condensates. [Pg.103]

Dew-point Temperature (DPT). DPT is the temperature at which the condensation of water vapor in a space begins for a given state of humidity and pressure as the temperature is reduced. It is the temperature corresponding to saturation (100% rh) for a given absolute humidity at constant pressure. [Pg.354]

Compounds having low vapor pressures at room temperature are treated in water-cooled or air-cooled condensers, but more volatile materials often requite two-stage condensation, usually water cooling followed by refrigeration. Minimising noncondensable gases reduces the need to cool to extremely low dew points. Partial condensation may suffice if the carrier gas can be recycled to the process. Condensation can be especially helpful for primary recovery before another method such as adsorption or gas incineration. Both surface condensers, often of the finned coil type, and direct-contact condensers are used. Direct-contact condensers usually atomize a cooled, recirculated, low vapor pressure Hquid such as water into the gas. The recycle hquid is often cooled in an external exchanger. [Pg.389]

Because of the wide variation in composition and properties of brown coal (see Table 3), efficient combustion of these fuels caimot be accomphshed by a single system. The moisture content limits combustion efficiency because some chemical energy is required to convert Hquid water to steam in the flue gases. The steam then increases the dew point of the gases, requiring higher temperatures to avoid condensation in the stack. For fuels up to 25% moisture content, 80% efficiency can be achieved. As the moisture content increases to 60%, the efficiency decreases to 70% and efficiency continues to decline about another 1% for each additional 1% moisture to 70%. [Pg.156]

Another nonregenerative drying appHcation for molecular sieves is their use as an adsorbent for water and solvent in dual-pane insulated glass windows. The molecular sieve is loaded into the spacer frame used to separate the panes. Once the window has been sealed, low hydrocarbon and water dew points are maintained within the enclosed space for the lifetime of the unit. Consequently, no condensation or fogging occurs within this space to cloud the window. [Pg.456]

N2, and traces of PH, CO2, E, and S large furnaces generate off-gas at a rate of about 120—180 m /min. In most installations the off-gas is passed through a series of Cottrell electrostatic precipitators which remove 80—95% of the dust particles. The precipitators ate operated at temperatures above the 180°C dew point of the phosphoms. The collected dust is either handled as a water slurry or treated dry. Einal disposal is to a landfill or the dust is partially recycled back to the process. The phosphoms is typically condensed in closed spray towers that maintain spray water temperatures between 20 and 60°C. The condensed product along with the accompanying spray water is processed in sumps where the water is separated and recycled to the spray condenser, and the phosphoms and impurities ate settled for subsequent purification. [Pg.351]


See other pages where Dew condensing is mentioned: [Pg.32]    [Pg.232]    [Pg.315]    [Pg.13]    [Pg.124]    [Pg.395]    [Pg.27]    [Pg.90]    [Pg.224]    [Pg.4]    [Pg.32]    [Pg.232]    [Pg.315]    [Pg.13]    [Pg.124]    [Pg.395]    [Pg.27]    [Pg.90]    [Pg.224]    [Pg.4]    [Pg.108]    [Pg.191]    [Pg.89]    [Pg.102]    [Pg.103]    [Pg.254]    [Pg.362]    [Pg.397]    [Pg.411]    [Pg.171]    [Pg.514]    [Pg.84]    [Pg.457]    [Pg.399]    [Pg.399]    [Pg.480]    [Pg.327]   
See also in sourсe #XX -- [ Pg.315 ]




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