Lead wire seals

In the design of the detonator attention must also be paid to the effects of the liberation of gas which, though small, is still sufficient to require attention. As the speed of the delay composition is affected by pressure, it is necessary that the free space in the detonator should be carefully controlled. Also, the plug which seals the leading wires in place must withstand this pressure for more than the delay period of the detonator. This task is made more difficult by conduction, along the metal walls of the detonator shell, of heat liberated by the fusehead and the delay composition. Plastic plugs in particular are liable to soften and be ejected from the detonator with probable failure of burning of the delay column. 

This material finds use as a sealing material in automotive applications and marine motor lead wire insulation. It has also been used as the base polymer for low flammability, halogen free, cable jacketing compounds. 

Figure 2 shows a photoelectric cell suitable for the direct determination of the photoelectric work function of a metal under the conditions of chemisorption. The electrically conducting catalyst, used as a cathode, either is inserted as a metal foil B or is evaporated from E to B. A metal layer coating the inside of the photoelectric cell serves as the anode, with a lead wire C. B can be heated electrically the leads fc are sealed into quartz and connected to an instrument (electrometer or amplifier) for... 

Cap A component on top of the bonnet used to restrict access and/or protect the set pressure adjustment screw. It may or may not be a pressure-containing part. In operation it should always be sealed with a leaded wire. 

Fig. 6. Beaker type celL A Pyrex beaker B Alundum membrane C Side-arm contact to the mercury pool consisting of a piece of glass tubing through which is sealed a piece of platinum D Thermometer E Reference electrode F Cathode lead wire G Nitrogen inlet and outlet tubes (for removal of peroxides from anode compartment) H Glass or teflon covered magnetic bar / Magnetic stirrer. (Taken from Ref., p. 34)...

Fig.3.122 shows a test sample attached to the frame. Leg wires are connected to leading wires, and the connection is sealed to be water-tight. The sample bottle is sunk to a depth of 1 m and is detonated. The first pulsating bubble is recorded. 

The cell consists of a small beaker with a top that will accommodate two electrodes as shown in Fig. 1. The cadmium electrode is made by plating cadmium onto a platinum wire that is sealed through the bottom of a small glass tube. The amalgam electrode is made by placing a small quantity of the cadmium amalgam in the cup of a special J-shaped glass tube with a platinum wire sealed into it. Electrical contacts are made by copper wires spot-welded to the platinum lead wires. 

Platinum can be used in the form of thin sheet or screen. Platinum wire can be welded to a small square of sheet or screen by placing it in position on a metal surface, heating to red heat with a torch, and striking lightly with a small ball peen hammer. The platinum wire can then be sealed into the end of a piece of soft-glass tubing. Electrical contact can be made by copper wire spot-welded to the platinum lead wire before the glass-to-metal seal is made. 

The thermal expansion of Dumet, as this composite wire is called, is about 7.0 x 10 per °C in the longitudinal direction of the wire, and in the radial direction it is about 9-1 x 10 per °C which is nearly the same as that of lead glass. Seals made between Dumet and lead glass are only partly annealed and the glass is left in compression in the longitudinal direction. 

With leads wired to the gauges and the current and voltage terminals, the test ring was mounted on the loading cones. After all the instruments were assembled, the test ring and loading cones were attached to the actuator, sealed into the helium dewar, precooled with liquid nitrogen, and immersed in liquid helium. 

Fabrication of fiber-optic electrode. Platinom was sputtered on the flat end surface of a plastic fiber-optic (diameter 2 mm, length ISO cm) courteously supplied by Mitsubishi Rayon Co. Sputtering was performed by a Hitachi minisputter for 5 min at 15 mA. The platinum counter electrode was prepared as illustrated in Figure 2. The thin platinum layer for the working electrode was connected to a lead wire with silver paste, while that for the counter electrode was connected with solder. The contact points were then fixed in place and insulated by sealing with epoxy resin. 

Measurement of Solution Conductivity. A typical cell for measuring solution conductivity is shown in Fig. 4.3.24. The cell is provided with inlets B and C, to fill it with the given electrolyte, and electrodes E and E, which are preferably platinized platinum. Electrical contact is made through the wires sealed in the glass wall. These electrical leads are also in contact with mercury in tubes A and D. The cross-sectional areas of the electrodes and the distance between them must be accurately determined in order to calculate the specific conductance. These precision measurements may be avoided by filling the cell compartment with solution of known specific conductance (usually a KCl solution of known concentration), and measuring the overall resistance, R. ... 

Industrial applications include pipe seals, hydraulic system seals, dampers for machinery and high speed printers, and motor lead wire insulation. The fact that the polymer contains no halogens along with certain unique compoimding techniques for flame resistance prompts the selection of ethylene-acrylic as jacketing material on certain transportation/military electrical cables, and in floor tiles. 

Seal Rubber Gasket Element Lead Wire... 

The cathode chamber has been designed for easy removal and addition of the catholyte (Fig. 5). The chamber is made from a medium porosity frit by cutting off one end of a No. lOM sealing tube next to the frit. In order to remove the catholyte, a piece of capillary tubing is inserted to within %0 in. of the frit and sealed into the tube. The cathode is a small piece of platinum foil fastened to a platinum wire and fitted around the capillary tube /2 in. from the frit. The platinum wire is attached to about 4 ft of lead wire and sealed into the top of the tube a small hole is made in the top of the chamber to allow air to escape, while a small funnel arm at the side facilitates catholyte addition. The portion of the capillary tube protruding from the chamber is bent at right angles... 

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