Vacuum creating

The drop in pressure when a stream of gas or liquid flows over a surface can be estimated from the given approximate formula if viscosity effects are ignored. The example calculation reveals that, with the sorts of gas flows common in a concentric-tube nebulizer, the liquid (the sample solution) at the end of the innermost tube is subjected to a partial vacuum of about 0.3 atm. This vacuum causes the liquid to lift out of the capillary, where it meets the flowing gas stream and is broken into an aerosol. For cross-flow nebulizers, the vacuum created depends critically on the alignment of the gas and liquid flows but, as a maximum, it can be estimated from the given formula. 

In a concentric-tube nebulizer, the sample solution is drawn through the inner capillary by the vacuum created when the argon gas stream flows over the end (nozzle) at high linear velocity. As the solution is drawn out, the edges of the liquid forming a film over the end of the inner capillary are blown away as a spray of droplets and solvent vapor. This aerosol may pass through spray and desolvation chambers before reaching the plasma flame. 

In designing for vacuum, credit may be taken for the fact that a vacuum situation may not create a full vacuum. Thus, not all vessels or equipment need be designed for a 100 % vacuinn situation. For example, if the vacuum situation is created by a blocked suction in a compressor circuit and the vacuum created is limited to 10 psia by die compressor characteristics, the system needs only to be designed for 10 psia. 

To maximize turbine efficiency (by minimizing turbine back-pressure). This is achieved by condensing steam and creating an adequate vacuum. The level of vacuum created by the reduction in steam-to-water volume is typically on the order of 26 to 29 inches of mercury and is in large part a function of the cooling water inlet temperature. A contribution to the maintenance of the vacuum is obtained through the mechanical pumps and air ejectors, which form part of the condenser system. 

All toilets on an aircraft are connected with one or more central tanks through vacuum pipes. This is illustrated in Figure 4. Solids are transported to the tanks by high vacuum, creating an air displacement of over 60 m per second. Up to flight altitudes of 4-5000 m, an electrical pump provides the necessary low pressure. In altitudes exceeding this level, the low pressure outside the aircraft provides the necessary pressure difference amounting to 0.5-0.6 bar. 

There are three common ways to deaerate a dissolution medium (1) vacuum filtration, (2) helium sparging, and (3) heating. Vacuum is commonly applied after filtration of the dissolution medium, with continued exposure of the filtrate to the low vacuum created by the aspirator (with or without heating). Potentially, the water pressure (i.e., degree of vacuum) of the water aspirator can affect this method of deaeration. Care should be taken to ensure that adequate suction has been applied. The time of exposure should be noted. 

In 2-2.5 h after termination of the reaction, decant the solution from the unreacted magnesium into a round-bottomed flask (Fig. 1196) close it with a stopper provided with a stopcock, and cool it in a bath with dry ice. Quench the vacuum created in the flask with argon (nitrogen), using the stopcock of the gas-discharge tube for this purpose. Pour off the mother liquor from the crystals (what is their composition ). If the separated crystals are yellow, recrystallize them from ether. Connect the flask with the crystals to a water-. 

Question Why is a vacuum created when water is squirted into the flask and why does the indicator change color when it enters the flask ... 

Before the acid truck was unloaded, acid started to overflow and pour through the six-inch (15 cm) line into the scrubber. The alert truck driver quickly responded. He abruptly shut the delivery valve on his truck. Unexpectedly, the partial vacuum created by the siphoning action of the overflowing liquid, exceeded the tank s vacuum rating and the storage tank was totally destroyed (see Figures 2—7, 2—8, and 2—9). [2]... 

For HF steps protective neoprene gloves, apron, and a plastic face shield should be worn. For the low HF step, add up to 4 g of resin to one of the Kel-F reaction vessels that are a part of the HF apparatus, and add 37.5 mL of a mixture of 90% dimethylsulfide, 5% p-thiocresol, 5% p-cresol and chill with liquid nitrogen and draw over 12.5 mL of anhydrous HF using vacuum created with a water driven aspirator to make a 25% HF solution. Remove liquid nitrogen. 

An easy way to perform the distillations of mercury amalgam is to construct a small retort using iron pipe fittings from the hardware store, pack charcoal briquettes around it and start the fire outside. Again the outlet is submerged in a container of water and the distillation of metallic mercury proceeds. When the distillation stops, be sure to remove the retort outlet from the water or the vacuum created by the cooling retort will draw the water into the apparatus with possible dire consequences, i.e. explosion. 

Turn on the tap to the water pump to the maximum water flow. If you do not do this, the water pump is not working at its maximum efficiency and the vacuum created in your filtration system may cause water to be sucked into a trap, or receiving flask, from the water pump. This is called suck-back . 

In principle, the semi-automatic gas titration device works by monitoring the partial vacuum created by a chemical reaction that consumes a gaseous substrate within a closed system.. 2 As the reaction progresses, the consumed gas is continually replenished in small uniform aliquots through a parallel set of solenoids connected to the reaction vessel and to a source of fresh reactant gas. 

A general schematic of the titration device is shown in Figure 1. The partial vacuum created by the gas consuming reaction is used to move mercury between two platinum electrodes in an electronically modified mercury manometer. When the mercury level has fallen from the top electrode, El, to just below the second electrode, E2, a process cycle controller activates the solenoids, B1 and B2. This solenoid action temporarily closes off the manometer to the reaction vessel and opens it to a source of reactant gas. Consequently, the loss in pressure is compensated by the introduction of fresh reactant gas to the manometer. The pressurization of the manometer forces the mercury level from below E2 back up to El. When the mercury level reaches El, the process cycle controller deactivates the solenoids. The... 

---