Siphoning

The Mariotte bottle. l he perchlorate guard tube is attached by a length of ordinary rubber condenser tubing to the Mariotte bottle W. This is, in effect, a siphon bottle, and the lead-in tube X is a capillary provided with a tap T,. The bent capillaiy (drawn off slightly at the end) serves as exit tube it is fitted into W by a rubber bung and its level may be adjusted. 

For solids of low density, the top of the porous thiinhle A should be above the siphon tube t. otherwise the solid may tend to float out of the thimble and pass down the siphon tube. 

Hydrobromic acid. Method 1 (from bromine and sulphur dioxide). A mixture of 600 g. (or 188-6 ml.) of bromine, 250 ml. of water and 760 g. of crushed ice is placed in a 1 6 litre round-bottomed flask and a rapid stream of sulphur dioxide (from a siphon of the liquefied gas) is passed into the flask, care being taken that the outlet of the gas-delivery tube is below the surface of the bromine layer. The rate of flow of the gas is adjusted so that it is completely absorbed. It is advisable to cool the flask in ice and also to shake the contents from time to time. The reduction is complete when the mixture assumes a uniform yellowish-brown or yellow colour, which is unaffected by further introduction of sulphur dioxide excess of the latter gas should be avoided as it will be... 

This acid mixture may be prepared (compare Section 11,49, 1) by placing 120 g. (37-5 ml.) of bromine and 130 g. of crushed ice in a 500 ml. flask, cooling the latter in ice, and passing sulphur dioxide (from a siphon of the liquefied gas) into the bromine layer at such a rate that the gas is completely absorb. The flask is shaken occasionally, and the flow of gas is stopped inunediately the red colour due to free bromine has disappeared the mixture will then have a yellow colour. The resulting acid mixture is equivalent to 260 g. of 48 per cent, hydrobromio acid to which 75 g. of concentrated sulphuric acid have been added it need not be dis. tilled for the preparation of n-butyl bromide. 

If the outlet of the siphon tube at the bottom of the Soxhlet apparatus is well plugged with cotton wool so that no finely-divided bariuna hydroxide can pass into the flask, the barium hydroxide may be placed directly into the extractor until the latter is three-quarters full the remaining space is filled with glass wool. 

Many continuous extractions involving solid samples are carried out with a Soxhiet extractor (Figure 7.18). The extracting solvent is placed in the lower reservoir and heated to its boiling point. Solvent in the vapor phase moves upward through the tube on the left side of the apparatus to the condenser where it condenses back to the liquid state. The solvent then passes through the sample, which is held in a porous cellulose filter thimble, collecting in the upper reservoir. When the volume of solvent in the upper reservoir reaches the upper bend of the return tube, the solvent and any extracted components are siphoned back to the lower reservoir. Over time, the concentration of the extracted component in the lower reservoir increases. 

By using a sampling device, the ions are siphoned from the end of the plasma flame and led into an ion mass analyzer, such as a quadrupole instrument, where the abundances of the ions and their m/z values are recorded. 

Ton-exchange systems in process appHcations may be batch, semicontinuous, or continuous. Batch operations are not common but, where used, involve a ketde with mechanical agitation. Injecting with air or an inert gas is an alternative. A screened siphon or drain valve is requited to prevent resin from leaving with the product stream. 

The slag is batch tapped into a receiving room where it is cooled and broken up for disposal. The metal buUion is tapped from the furnace periodically via a siphon into 2-t cast-iron molds. Typical buUion content from an electric furnace in wt % is Sb, 13—18 Sn, 1—2 As, 0.5—1 Cu, 0.3—0.4 and Ni, 0.05—0.1. The balance is lead. 

Molten aluminum is removed from the cells by siphoning, generally daily, into a cmcible. Normally the metal is 99.6—99.9% pure. The principal impurities are Ee, Si, Ti, V, and Mn, and come largely from the anode, but also from the alumina. 

Another type of experiment involves a fluid filament being drawn upward against gravity from a reservoir of the fluid (101,213,214), a phenomenon often called the tubeless siphon. The maximum height of the siphon is a measure of the spinnabiUty and extensional viscosity of the fluid. Mote quantitative measures of stress, strain, and strain rate can be determined from the pressure difference and filament diameter. A more recent filament stretching device ia which the specimen is held between two disks that move apart allows measurements ia low viscosity Hquids (215). AH of these methods are limited to spinnable fluids under small total strains and strain rates. High strain rates tend to break the column or filament. 

Even when their shells are closed, the animals continue to sense their environment, and as soon as the oxidant level decreases, they reopen and resume siphoning. Continuous chlorination often fails to eradicate these macrofouling creatures because of iatermptions ia the feed, which can occur for various reasons, such as chlorine tank changeover or plugging of feedlines. If the iatermption lasts long enough (1 h or possibly less), the animals have time to reoxygenate their tissues between the extended periods of chlorination. Any oxidant, such as chlorine, bromine, or ozone, eUcits the same response from these creatures. Therefore, only continuous, unintermpted appHcations are successful. 

Ejectors and injectors are the two types of jet pumps of interest to chemical engineers. The ejector, also called the siphon, exhauster, or eductor, is designed for use in operations in which the head pumped against is low and is less than the head of the fluid used for pumping. 

The simple ejector or siphon is widely used, in spite of its low efficiency, for transferring liquids from one tank to another, for lifting acids, alkahes, or solid-containing liquids of an abrasive nature, and for emptying sumps. 

Rotary-Siphon Peeler Centrifuges In this type of centrifuge, a partial vacuum is drawn on the outer diameter or tne filter such that the filtrate flows through the cake under both centrifugal force as well as a positive pressure difference of about I atm or less. Thus, a higher rate of filtration takes place due to the increased driving force. 

The suction pressure generated is equal to the liquid head difference across the annular baffle as magnified by G. The maximum suction that can be realized, assuming neghgible vapor pressure, is I atm. For example, with a differential liquid level of 2 cm (0.79 in) of water across the annulus under 500g, the suction generated by the siphon is 0.98 atm. 

Pressurized Siphon Basket Centrifuges In addition to a siphoning action downstream of the filter, an additional pressure difference of as much as 5 to 6 atm is imposed across the filter to further... 

Hydraulic cylindrical tank classifier Om tp (M-F) Hydraulic form of overloaded thickener. Siphon-Sizer (N-F) uses siphon to discharge underflow instead of rotating rake. 1.0 to 40 1.4 mm to 45 im (25 mm) 1 to 150 Not critical 0.4 to 15 20 to 35 0.75 to 11 Two-product device giving very clean underflow. Requires relatively little hydraulic water (2 t/t solids feed). Used for washing, desliming, and closed circuit grinding. 

Coarse solids are discharged by siphons extending to the bottom of the hindered-settling zone. Siphon control is obtained by a novel hydrostatically actuated valve which makes or breaks the siphon to flow only when the teeter zone is in correct condition. Discharge by an intermediate fraction from the upper column is by means of additional siphons. Hydraulic-water consumption is considerably lower than required for multipocket sizers. 

Siphoning of liquids Less obvious causes include ... 

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