Nichrome wire

The furnace and thermostatic mortar. For heating the tube packing, a small electric furnace N has been found to be more satisfactory than a row of gas burners. The type used consists of a silica tube (I s cm. in diameter and 25 cm. long) wound with nichrome wire and contained in an asbestos cylinder, the annular space being lagged the ends of the asbestos cylinder being closed by asbestos semi-circles built round the porcelain furnace tube. The furnace is controlled by a Simmerstat that has been calibrated at 680 against a bimetal pyrometer, and the furnace temperature is checked by this method from time to time. The furnace is equipped with a small steel bar attached to the asbestos and is thus mounted on an ordinary laboratory stand the Simmerstat may then be placed immediately underneath it on the baseplate of this stand, or alternatively the furnace may be built on to the top of the Simmerstat box. 

Excellent results are obtained by passing acetone vapour over an electrically heated nichrome wire spiral an apparatus, incorporating the latter, is described in the experimental section. 

Chapter III. 1 Heptene (111,10) alkyl iodides (KI H3PO4 method) (111,38) alkyl fluorides (KF-ethylene glycol method) (111,41) keten (nichrome wire method) (111,90) ion exchange resin catalyst method for esters (111,102) acetamide (urea method) (111,107) ethyl a bromopropionate (111,126) acetoacetatic ester condensation using sodium triphenylmethide (111,151). 

A heavy nichrome wire twisted into 4 loops (similar to an egg beater) was found to be very satisfactory. The two ends of the wire, extending several inches beyond the loops, were pushed into a piece of glass tubing for the stirrer shaft. 

Hot wire anemometer An instrument for the measurement of fluid velocity by measuring the resistance of a fine platinum or nichrome wire, which may or may not be shielded by a silica tube. The wire resistance is proportional to the temperature and the fluid flow rate. 

It has been observed2 that the dropwise addition of an aqueous solution of potassium ethyl xanthate to a cold (0°) aqueous solution of diazotized orthanilic acid results in the immediate loss of nitrogen when a trace of nickel ion is present in the stirred diazonium solution.3 The catalyst can be added as nickelous chloride or simply by using a nichrome wire stirrer. When no nickel ion is added and a glass stirrer is employed, the diazonium xanthate precipitates and requires heat (32°) to effect decomposition. 

The main sources of infrared radiation used in spectrophotometers are (1) a nichrome wire wound on a ceramic support, (2) the Nernst glower, which is a filament containing zirconium, thorium and cerium oxides held together by a binder, (3) the Globar, a bonded silicon carbide rod. These are heated electrically to temperatures within the range 1200- 2000 °C when they will glow and produce the infrared radiation approximating to that of a black body. 

Reactor type Chip micro reactor with Z-type flow configuration Heater type/material Nichrome wire... 

The heater can be made from Nichrome wire wound in the form of... 

Glass-working shops that are called upon to make large or intricate apparatus should be equipped with an annealing oven. With some ingenuity a home-made one can be built using Nichrome wire and fire-brick. 

After scratching, 26 s.w.g. (or thicker) Nichrome wire is wrapped once round the scratch, which is wetted. The wire is heated to redness electrically, and kept taut round the glass—for this purpose it is convenient to have insulated handles on the wire. The tubing may then crack smoothly if not, it may be induced to crack by touching the scratch with wetted asbestos when the wire has been hot for about half a minute. An internally scratched Pyrex tube may not crack until it is put in a flame. 

For tooling of molten Vitreosil inch Nichrome wire may be employed though if much tooling is required, then carbon rods or plates are necessary. In general, most of the operations described in earlier chapters can be modified for working with Vitreosil and, if a sufficiently hot flame is available, less manipulative skill is usually necessary because the material stays fairly viscous. 

Using an 8-in. Nichrome wire strip connected with springs to a variac, organic decomposition can be carried out in a very fine line to locate zones. The resulting carbon is small in quantity and will not interfere in subsequent elutions. 

The condenser, attached to the flask by a ground-glass joint, is a Pyrex tube 50 cm. long and 20 mm. in internal diameter, wound with No. 26 Nichrome wire covered with asbestos paper. It is connected to a variable transformer and adjusted so as to maintain a temperature of 100-110°. A copper Liebig condenser heated by steam is also suitable provided that the inner tube has a diameter of about 20 mm. 

Aerosols generated by electrical heating of a coil of nichrome wire Aerosol Size Range 0.01 - 0.08 urn (radius)... 

A piece of nichrome wire is first cleaned by dipping it into concentrated hydrochloric acid. 

A Hershberg nichrome wire stirrer2 is well suited for this reaction. 

The UN DDT tests [22] are used to investigate this phenomenon. These tests are, in principle, similar to the tube tests described in Section 2.3.3.1, but as an initiation source, a hot nichrome wire, or a nichrome wire surrounded by black powder, placed in the center of the tube is used instead of a detonation booster. 

Radiation in the infrared region of the spectrum is obtained from heated ceramic devices such as the Nemst glower or Globar. The Globar is made of silicon carbide and is heated to approximately 800-1500°C to emit black-body radiation in the infrared region of the spectrum. Coils of nichrome wire also emit infrared radiation when electrically heated. 

When the osmometer is in operation, a nichrome wire of a suitable diameter is inserted into the capillary (the diameter of the wire is almost equal to the inner diameter of the capillary). The wire serves for adjusting the liquid level in the measuring capillary and is held in the capillary with the aid of a cork. 

First of all the solution is introduced into the cell and then the nichrome wire is inserted into capillary-4... 

Given the unreliability of the stab-initiated tests, a second round of testing was performed using a hot nichrome wire to initiate the detonators in place of the NOL-130 stab mix and firing pin. This test was successful and all nine detonators functioned, showing that DBX-1 is more susceptible to this method of initiation. Figure 8 shows the electrical ignition setup. 

The glass helices may be purchased from the Scientific Glass Apparatus Company, Bloomfield, N. J., or the American Instrument Company, Silver Spring, Md. Wire helices are readily made from No. 18 B. and S. gauge copper or Nichrome wire, by simultaneously winding two strands side by side on a j-in. steel mandrel. The spirals are cut into single helices by means of a thin emery wheel and then removed from the mandrel. 

Rowe and Henwood(26) made similar studies by supporting a spherical particle 12.7 mm diameter, in water, at the end of a 100 mm length of fine nichrome wire. The force exerted by the water when flowing in a 150 mm square duct was calculated from the measured deflection of the wire. The experiments were carried out at low Reynolds numbers with respect to the duct (< 1200), corresponding to between 32 and 96 relative to the particle. The experimental values of the drag force were about 10 per cent higher than those calculated from the Schiller and Naumann equation. The work was then extended to cover the measurement of the force on a particle surrounded by an assemblage of particles, as described in Chapter 5. 

The heat exchanger consists of a small centrifugal fan that takes air from outside the unit and forces it, via ducts, into the four corners of the sample chamber. A heater made from Nichrome wire wound around a ceramic former is situated within the ducting immediately upstream of the fan. The temperature within the sample chamber is monitored by a thermistor set in the floor of the chamber and a proportional temperature controller maintains the temperature at 60°C. 

Respiratory Effects. Pleural effusions and alveolar infiltrations were noted in a man who had washed his hair with an unknown amount of diesel fuel (Barrientos et al. 1977). The relative contributions from inhalation and dermal exposure could not be distinguished in this case. There was no throat irritation in six volunteers following a 15-minute exposure to a concentration reported to be 140 mg/m of deodorized kerosene vapor (Carpenter et al. 1976). The authors used a hot nichrome wire for the volatilization of their test material and reported that the concentration was probably the "highest attainable concentration at which vapor analysis is representative of liquid analysis." The air saturating concentration of kerosene is considered to approximate 100 mg/m (room temperature and 760 mmHg) and is dependent on the constituents of the mixture. 

In reactions in which HC1, HBr, or HI are evolved there is a convenient way of detecting and following the course of the reaction. Gas will be evolved and a bead of silver nitrate solution in a small loop of nichrome wire placed in this gas stream will become opaque, if these gases are present. Hydrogen fluoride will not do this since silver fluoride is very soluble in water. If a simple test for hydrogen fluoride is desired, a similar bead of calcium chloride will serve very well. 

Explosions by Hot Wires. Ignition failures with thin nichrome wires in methane-air were due to fusion of the wire before sufficient energy had been communicated to the gas to effect ignition... 

The submitters used a pint hydrogenation bottle wound with 30 ft. of No. 24 Nichrome wire insulated with asbestos paper. Before the reaction the current was adjusted by means of a variable transformer so that the solution was maintained at approximately 70° during the reaction. The checkers used a 500-ml. centrifuge bottle without provision for heating. 

Colouring of a Flame by Lithium, Sodium, and Potassium Salts. Introduce a platinum or nichrome wire into the colourless flame of a burner. If the flame becomes coloured, wash the wire with pure hydrochloric acid and roast it in the burner flame until the latter becomes colourless. Wet a platinum wire in a potassium chloride solution and introduce it into the colourless flame of the burner. What do you observe Perform similar experiments with solutions of sodium and lithium chlorides. Observe the colouring of the flame by the potassium salts through an indigo prism. 

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