Sealing washers copper

Sealing washers made of copper are still encountered in old HR systems. 

NB Copper sealing washers are single-use seals and they must be replaced each time the mould is cooled down. Furthermore, they should not be used in the processing of some plastics because of the destructive effect of copper (see Chapter 3). 

The tracer composition is frequently housed in a metal canister placed inside the base cavity. Copper, brass, gilding metal, gilding metal-coated steel, and copper-coated steel canisters are known. Some compositions are placed into the hollow base cavity without the use of a canister. A typical tracer bullet consists of a gilding metal bullet jacket and a lead core with a base cavity containing the tracer composition. Paper discs and lead, steel, or brass washers sealed with varnish are sometimes used to seal the base of the bullet. 

Figure 1 Matrix apparatus as used in Nottingham (1) valve power supply, (2) helium pressure connections to compressor, (3) silicon diode and heater lead-through, (4) pump-out port, (5) gas inlet port, (6) cold station, (7) heater and thermocouple wires, (8) stainless steel tube, (9) silicon diode, (10) very cold station and heater sleeve, (11) cell, (12) photolysis and spectroscopic windows, for an experiment the cell is turned by 90° towards the windows, (13) vacuum shroud, (14) large half of cell, (15) small half of cell, (16) IR optical windows, (17) lead seal, (18) indium window seal, (19) circlip retainer groove, (20) bolt, (21) steel washer, (22) spring washer, (23) nut, (24) femal-femal union, (25) steel tubing, (26) to very cold station, (27) threaded copper stud, (28) threaded hole in large half of cell to receive stud, (29) indium joints, (30) circlip, which fits in groove and retains windows.

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