Mercury vapour tubes

A short length of 23 mm tubing is attached to the mercury vapour tube, cut off at a slight angle to the horizontal and flanged out in preparation for sealing to the outer jacket. 

The outer jacket of the condenser and the boiler are now cut to length. The mercury vapour tube and jets are supported in the centre of the condenser with corrugated paper, or with a suitable number of layers of ordinary paper. 

Cinnabar Electron tubes containing mercury Mercuric salt Mercurous compound Mercury compound, liquid, n.o.s, 6.1 Mercury compound, solid, n.o.s., 6.1 Mercury contained in manufactured articles, 8 Mercury vapour tubes Phenylmercuric compound, n.o.s., 6.1 Quicksilver... 

If the pump is a filter pump off a high-pressure water supply, its performance will be limited by the temperature of the water because the vapour pressure of water at 10°, 15°, 20° and 25° is 9.2, 12.8, 17.5 and 23.8 mm Hg respectively. The pressure can be measured with an ordinary manometer. For vacuums in the range lO" mm Hg to 10 mm Hg, rotary mechanical pumps (oil pumps) are used and the pressure can be measured with a Vacustat McLeod type gauge. If still higher vacuums are required, for example for high vacuum sublimations, a mercury diffusion pump is suitable. Such a pump can provide a vacuum up to 10" mm Hg. For better efficiencies, the pump can be backed up by a mechanical pump. In all cases, the mercury pump is connected to the distillation apparatus through several traps to remove mercury vapours. These traps may operate by chemical action, for example the use of sodium hydroxide pellets to react with acids, or by condensation, in which case empty tubes cooled in solid carbon dioxide-ethanol or liquid nitrogen (contained in wide-mouthed Dewar flasks) are used. 

Potassium (metal) [7440-09-7] M 39.1, m 62.3 , d 0.89. Oil was removed from the surface of the metal by immersion in n-hexane and pure Et20 for long periods. The surface oxide was next removed by scraping under ether, and the potassium was melted under vacuum. It was then allowed to flow through metal constrictions into tubes that could be sealed, followed by distillation under vacuum in the absence of mercury vapour (see Sodium). EXPLOSIVE IN WATER. 

A diagram of a suitable apparatus is shown in Fig. 21.7. The mercury vapour is flushed out of the reaction vessel by bubbling argon through the solution, into the absorption tube. 

MDHS 14 General method for the gravimetric determination of respirable and total dust MDHS 15 Carbon disulphide MDHS 16 Mercury vapour in air Laboratory method using hopcalite adsorbent tubes, and acid dissolution with cold vapour atomic absorption spectrometric analysis MDHS 17 Benzene in air Laboratory method using charcoal adsorbent tubes, solvent desorption and gas chromatography MDHS 18 Tetra alkyl lead compounds in air Continuous on-site monitoring method using PAC Check atomic absorption spirometry... 

MDHS16 Mercury vapour in air (hopcalite adsorbent tubes). 

Moore [355] used the solvent extraction procedure of Danielson et al. [119] to determine iron in frozen seawater. To a 200 ml aliquot of sample was added lml of a solution containing sodium diethyldithiocarbamate (1% w/v) and ammonium pyrrolidine dithiocarbamate (1 % w/v) at pH to 4. The solution was extracted three times with 5 ml volumes of 1,1,2 trichloro-1,2,2 trifluoroethane, and the organic phase evaporated to dryness in a silica vial and treated with 0.1 ml Ultrex hydrogen peroxide (30%) to initiate the decomposition of organic matter present. After an hour or more, 0.5 ml 0.1 M hydrochloric acid was added and the solution irradiated with a 1000 W Hanovia medium pressure mercury vapour discharge tube at a distance of 4 cm for 18 minutes. The iron in the concentrate was then compared with standards in 0.1 M hydrochloric acid using a Perkin-Elmer Model 403 Spectrophotometer fitted with a Perkin-Elmer graphite furnace (HGA 2200). 

Frequently colourless substances can also be separated and purified by this procedure provided that the chromatogram, prepared in a tube of special glass or quartz, can be divided up in the light of a mercury vapour lamp, in accordance with the fluorescence induced. For example, carotene has thus been separated into three components (R. Kuhn, P. Karrer). 

A system for cold vapour AAS is shown in Fig. 7.3. The evolved mercury vapour is passed to a long path-length absorption cell, usually constructed of Pyrex glass tubing with silica end windows. A transient absorption peak is observed. In some systems, a recirculating pump is used to cycle the mercury vapour around the system and achieve a steady reading. 

Diverse instruments employing the principle of this experiment are used to measure mercury, a toxic and volatile element, present in many work areas. A device has been designed as a colorimeter dedicated for this single element. The source is a mercury vapour lamp and the cell is a transparent tube filled with the atmosphere to be monitored. If mercury vapours are present in the optical path, absorption of radiation emitted by the lamp will occur and this will lead to a decrease in the transmitted light intensity measured by the instrument. 

Figure 7.2. Schematic diagram of the static mercury vapour apparatus. A Absorption cell B metal support C PTFE tubing D reduction vessel E silicone rubber F magnetic bar G magnetic stirrer H PTFE tubing Iq incident beam intensity I transmitted beam intensity and J exhaust. From [34]...

Hanau Q 81 high-pressure mercury - vapour lamps fitted into Pyrex tubes were used as the radiation source for these acetone-initiated reactions. 

If mercury ions in solution are reduced to the free element, and a current of air or inert gas is passed through the solution, mercury vapour, which is monatomic, will be swept out of the solution into the gas phase. This provides a very sensitive basis for the determination of this toxic element.1 The apparatus required is illustrated in Figure 1. The flame is replaced by a glass tube atom cell with silica end windows in atomic absorption. Usually, for convenience, the atom cell is clamped to the top of a conventional AAS burner head. If atomic fluorescence is... 

The arc is ignited by means of an ignition needle which carries auxiliary anode H at first this is electromagnetically drawn into the mercury-filled dish then the contact is interrupted which gives rise to an arc which spreads quickly to anodes A. The necessary vacuum in the tubes, some 0.001 millimeters of mercury column (apart from the partial pressure of mercury vapour) is maintained by a diffusion vacuum pump compounded with an oil type rotary vacuum pump. 

In case of mechanical damage, the environmental atmosphere enters the tube and starts to compress the filling gas of the lamp. The filling gas is composed of (normally) argon and mercury vapour at a total pressure of some 102Pa. The compression proceeds without any energy transfer to the environment as an adiabatic compression, described by Poisson s law ... 

In the same manner, temperatures exceeding the ignition temperatures (see Table 1.3 in Section 1.2.2) or the maximum surface temperatures according to the temperature class of the apparatus (see Table 4.1 in Chapter 4) are permissible inside of d. This covers windings and rotors in motors, especially for low temperature classes T4, T5 and T6 as well as the discharge tubes of high pressure sodium or mercury vapour lamps in case of a broken lamp bulb, or the ovens of gas chromatographs. 

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