Atmospheric pressure pumping

Chill the concentrated solution of the amine hydrochloride in ice-water, and then cautiously with stirring add an excess of 20% aqueous sodium hydroxide solution to liberate the amine. Pour the mixture into a separating-funnel, and rinse out the flask or basin with ether into the funnel. Extract the mixture twice with ether (2 X25 ml.). Dry the united ether extracts over flake or powdered sodium hydroxide, preferably overnight. Distil the dry filtered extract from an apparatus similar to that used for the oxime when the ether has been removed, distil the amine slowly under water-pump pressure, using a capillary tube having a soda-lime guard - tube to ensure that only dry air free from carbon dioxide passes through the liquid. Collect the amine, b.p. 59-61°/12 mm. at atmospheric pressure it has b.p. 163-164°. Yield, 18 g. 

Receiver adapters or connectors. Various forms of receiver adapters are shown in Figs. 11, 56, 26-29. The simplest form. Fig. 11, 56, 26, carries a glass hook for securing it to the condenser by means of a rubber band from the side tube to the hook an improved form, incorporating two ground glass joints is shown in Fig. 11, 56, 27. A useful adapter is illustrated in Fig. 11, 56, 28 when employed at atmospheric pressure, a drying tube may be attached to the side tube, if desired in a distillation under reduced pressure, the side tube is connected to the pump. Fig. 11, 56, 29 depicts a receiver adapter with an additional socket connection. 

Liberate the free base by adding to the phenylhydrazine hydrochloride 125 ml. of 25 per cent, sodium hydroxide solution. Extract the phenyl-hydrazine with two 40 ml. portions of benzene, dry the extracts with 25 g. of sodium hydroxide pellets or with anhydrous potassium carbonate thorough drying is essential if foaming in the subsequent distillation is to be avoided. Most of the benzene may now be distilled under atmospheric pressure, and the residual phenylhydrazine under reduced pressure. For this purpose, fit a small dropping funnel to the main neck of a 100 ml. Claisen flask (which contains a few fragments of porous porcelain) and assemble the rest of the apparatus as in Fig. II, 20, 1, but do not connect the Perkin triangle to the pump. Run in about 40 ml. of the benzene, solution into the flask, heat the latter in an air bath (Fig. II, 5, 3) so that... 

Ethyl phenylethylmalonate. In a dry 500 ml. round-bottomed flask, fitted with a reflux condenser and guard tube, prepare a solution of sodium ethoxide from 7 0 g. of clean sodium and 150 ml. of super dry ethyl alcohol in the usual manner add 1 5 ml. of pure ethyl acetate (dried over anhydrous calcium sulphate) to the solution at 60° and maintain this temperature for 30 minutes. Meanwhile equip a 1 litre threenecked flask with a dropping funnel, a mercury-sealed mechanical stirrer and a double surface reflux condenser the apparatus must be perfectly dry and guard tubes should be inserted in the funnel and condenser respectively. Place a mixture of 74 g. of ethyl phenylmalonate and 60 g. of ethyl iodide in the flask. Heat the apparatus in a bath at 80° and add the sodium ethoxide solution, with stirring, at such a rate that a drop of the reaction mixture when mixed with a drop of phenolphthalein indieator is never more than faintly pink. The addition occupies 2-2 -5 hoius continue the stirring for a fiuther 1 hour at 80°. Allow the flask to cool, equip it for distillation under reduced pressure (water pump) and distil off the alcohol. Add 100 ml. of water to the residue in the flask and extract the ester with three 100 ml. portions of benzene. Dry the combined extracts with anhydrous magnesium sulphate, distil off the benzene at atmospheric pressure and the residue under diminished pressure. C ollect the ethyl phenylethylmalonate at 159-160°/8 mm. The yield is 72 g. 

The so-called hyperbar vacuum filtration is a combination of vacuum and pressure filtration in a pull—push arrangement, whereby a vacuum pump of a fan generates vacuum downstream of the filter medium, while a compressor maintains higher-than-atmospheric pressure upstream. If, for example, the vacuum produced is 80 kPa, ie, absolute pressure of 20 kPa, and the absolute pressure before the filter is 150 kPa, the total pressure drop of 130 kPa is created across the filter medium. This is a new idea in principle but in practice requires three primary movers a Hquid pump to pump in the suspension, a vacuum pump to produce the vacuum, and a compressor to supply the compressed air. The cost of having to provide, install, and maintain one additional primary mover has deterred the development of hyperbar vacuum filtration only Andrit2 in Austria offers a system commercially. 

Gas Transport. Initially, ia a vessel containing air at atmospheric pressure, mass motion takes place when temperature differences exist and especially when a valve is opened to a gas pump. Initial dow ia practical systems has been discussed (29), as have Monte Cado methods to treat shockwave, turbulent, and viscous dow phenomena under transient and steady-state conditions (5). 

Air leaks into the system if the pump suction is below atmospheric pressure. 

The noncondensable gases eventually reach the condenser (unless vented from an effect above atmospheric pressure to the atmosphere or to auxiliary vent condensers). These gases will be supplemented by air dissolved in the condenser water and by carbon dioxide given off on decomposition of bicarbonates in the water if a barometric condenser is used. These gases may be removed by the use of a water-jet-type condenser but are usually removed by a separate vacuum pump. 

In the operational sense, some filters are batch devices, whereas others are continuous. This difference provides the principal basis for classifying cake filters in the discussion that follows. The driving force by which the filter functions—hydrostatic head ( gravity ), pressure imposed by a pump or a gas blanket, or atmospheric pressure ( vacuum )— will be used as a secondary criterion. 

These pumps are used to lift deep groundwater or any other liquid from hard or rocky soil. Moreover, the liquid level may be so deep that it may prevent the use of a centrifugal pump. Theoretically, the maximum depth from which water can be lifted against atmospheric pressure is 9.8 m (32 feet). To lift water or any other liquid from... 

Pump manufacturers express vacuum in aspirated feet of water in a ver r -i (0 psia = -33.9 feet of water). The pharmaceutical and chemical indue r Pascals (100,000 Pascals = atmospheric pressure) and the term TO C. conglomeration of values and conversion n, causes confusion. In ( ... 

To determine the Ha, atmospheric head, you only need observe the vessel being drained by the pump. Is it an opened, or vented atmospheric vessel Or is it a dosed and scaled vessel If the vessel is open, then we begin with the atmospheric pressure expressed in feet, which is 33.9 feet at sea level. The altitude is important. The atmospheric pressure adds energ) to the fluid as it enters the pump. For closed un-pressurized vessels the Ha is equal to the Hvp and they cancel themselves. For a dosed pressurized vessel remember that every 10 psia of pressure on a vessel above the vapor head of the fluid will add 23.1 feet of Ha. To the Ha, we add the Hs. 

Reply If you could really suck on the milk, then you wouldn t need the straw. -you re actually doing with your mouth on the straw is lowering the atmospi pressure inside the straw, so that the atmospheric pressure outside the straw pu the milk up into your mouth. This is why we say that a pump does not The p-r.ip actually generates a zone of low pressure in. . eye of the impeller, thereby Ic,-" ig the atmospheric pressure inside the suction piping. Atmospheric pressure outside the suction piping pushes the liquid up toward the impeller a maximum of 34 ft under ideal circumstances. 

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