Open to atmosphere

Fig. 5. Vacuum caUbrator for pipe and tubing extmsion A, molten tube from die B, tank C, hinged cover with gasket D, siting rings E, circulated and temperature controlled water E, water level G, vacuum and H, inside of pipe open to atmospheric pressure (15).

Compartments within the valve separate the various zones to ensure that the separation is sharp and no mixing of mother, strong, middle and weak filtrates occurs during the cycle. To speed up the evacuation of the various filtrates there are valves with two bridge circles, one for the main stream and the another that opens to atmosphere and purges the pan below the deck just before entering a new zone. 

The plate heat exchanger consists of a frame in which closely spaced metal plates are clamped between a head and follower. The plates have corner ports and are sealed by gaskets around the ports and along the plate edges. A double seal forms pockets open to atmosphere to prevent mixing of product and service liquids in the rare event of leakage past a gasket. 

All efforts should be made to eliminate these kinds of operating practices. Thus, where condensate receivers are fully open to atmospheric pressure (vented), efforts should be made to limit the absorption of oxygen at the water surface by raising the water level (where horizontal cylindrical tanks are used) or by covering the water surface (thermally resistant plastic balls are sometimes employed). 

Liquid flows from an upstream source, at pressure Pi, via a fixed position valve into the tank, at pressure P2. The liquid in the tank discharges via a second fixed position valve to a downstream pressure P3. The tank can be open to atmosphere, closed off to the atmosphere and can work either under isothermal or adiabatic temperature conditions. The detailed derivation of this problem is discussed both by Franks (1972) and Ramirez (1976, 1989). Data values in the problem are similar to those of Ramirez, who also made simulations of this problem. 

It is usual to encounter in studies of energy changes associated with reactions of chemical interest, a great variety of chemical materials and transformations. There are many ways by which transformations are implemented but it is convenient to consider two conditions that are special and occur frequently (i) the volume of the system is kept constant and (ii) the pressure on the system is held constant. The second scenario, for example, is that occurring for reactions or other processes carried out in containers that are open to atmosphere. 

Propane dryer vent valve inadvertently left open to atmosphere... 

Figure 6.27 shows the XPS spectra of the pyrite surface under different conditions. The characteristic peaks Ca(2p),Ca(2s) and Fe disappear by the addition of oxalic acid when compared to spectra in the absence of activator. In the XPS extended spectra for oxygen and carbon (presenting since the system is open to atmosphere) at the pyrite surface, no change is found after the addition of oxalic acid, indicating that no adsorption of oxalate occurs at the pyrite surface. The results in Fig. 6.27 also indicate that the soluble complexes formed by activators with cation hydroxides of Ca(OH)2 and Fe(OH)3 desorb from the pyrite surface. 

The subsurface generally is an open system. The presence of CO and other gases in the atmosphere affects the partial pressure of gas constiments in the subsurface. For example, carbonate mineral dissolution in a system open to atmospheric COj does not achieve equilibrium. However, higher local subsurface CO concentrations can originate from biological activity and other oxidation processes. 

There were also differences between the two excerpts. For example, no mention was made of a flask or beaker in excerpt 3K however, the authors mention a three-necked 3 L round-bottomed flask in excerpt 3L. Similarly, no hood is mentioned in excerpt 3K, but the authors mention a hood, open to atmosphere, in excerpt 3L. What principles guided these decisions Although there are no hard and fast rules, you should include common details (e.g., a flask or hood) only if you want to draw attention to those steps (as in excerpt 3L). (See figure 3.2.)... 

With the stopcock closed to the flask and open to atmosphere, move the levelling bulb until the level of water in the burette is at zero. f)Open the stopcock to the flask and tip the apparatus slightly to make the glass cylinder(inside the flask) fall. g)Contact of A1 with KOH soln will cause the evoln of hydrogen and movement of the level of water in the burette. The reaction lasts about 1 hour. From the volume of hydrogen evolved the amt of A1 is calcd. h)If there is any black residue in the flask, the presence of carbon is indicated and if the residue is... 

A stream of dry air blows across the open top of the tube. Thereby the concentrations (or equivalently the mole fractions) of HC1 and H2O at the z = Z are assumed to drop to zero. For this example, assume a tube height of Z = 0.1 m, open to atmospheric pressure (i.e, p = 101325 Pa). The mole fractions of HC1 and H2O at the liquid-vapor interface are assumed to be at their equilibrium values, 0j01395, and 0.00712, respectively [312]. 

A very simple means by which liquid level is measured in a vessel is by the gauge glass method (Figure 1). In the gauge glass method, a transparent tube is attached to the bottom and top (top connection not needed in a tank open to atmosphere) of the tank that is monitored. The height of the liquid in the tube will be equal to the height of water in the tank. 

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