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Electrode clamps for spectrochemical analysis
Spectrochimics Acta, 1952, Vol. 4, pp. 472. Pergamon Press Ltd., London
Electrode clamps for spectrochemical analysis R. 0. SCOTTand A. M. FRASER Macaulay Institute
for Soil Research, (Received
Craigieburkler,
Aberdeen
12 October 1951)
The need for a simple and efficient holder for graphite, carbon or metal elect,rodes up to 14in. in diameter has often been felt in this laboratory, as none of t’hose commercially available has been found convenient in routine operation. The spring loaded clamp described here has been designed part’icularly for spark and pulsed arc operation and is easily carried in the Hilger de Grarnont st,and. In addition to its simplicity, t’hree points in the design are worth emphasizing: spring loading 5 permits rapid change of electrode ; as the 7q electrode can be inserted from the open end of the clamp there is no contamina3 tion of either end; the clamp can be , readily dismantled and assembled. \r The arms (1) and (2) of the clamp are 6 of mild steel 2Q in. by 4 in. by $ in., with b f grooves, i:in. deep and 90” included angle. 9’ , _I for posit,ioning the fulcrum (3), whilst (1) 7ff has a similar groove (4) to position the / electrode. The fulcrum (3) can either be 2’ a 2 in. by 3 in. dowel pin as shown, or Fig. 1. Spring loaded electrode clamp-unit to carry upper electrode. can have shoulders to prevent vertical displacement of the arms. At the jaws the height is reduced to 14 in. to facilitate t’he employment of short electrodes, whilst the arms are slotted at the other end to clear the spring, and Tufnol* finger knobs (5) for opening the clamp, are fitted into these slots and held by 1i in. dowel pins (7). At the knob ends the arms are filed on the inside surfaces until a, $ in. diameter rod can just, be introduced laterally into the jaws. The pillar (S), h in. by 14 in., for holding the clamp in a Hilger type arc stand is screwed into arm (1). The spring (9) is a single coil cut from a one inch diameter 14 SWG steel spring, and displacement is prevented by small depressions (10) in the arms 4 in. from the fulcrum. These springs are easily renewed should they lose their tension and any required tension can be obtained either by changing t’he position of the depressions relative to the fulcrum, or by using a different thickness of wire. The heating of the spring from contact with the arms is slight, since the only direct’ points of contact are at the ends of the coil. The construction is simple, the end of the supporting pillar being the only screwed part. It might appear feasible to use the fulcrum, somewhat lengthened, as the pillar, but experience has shown this to be undesirable.
-“\g!_:;
* A reinforce plastic insulating material. 472
Electrode clamps for spectrochemical analysis R. 0. SCOTTand A. M. FRASER Macaulay Institute
for Soil Research, (Received
Craigieburkler,
Aberdeen
12 October 1951)
The need for a simple and efficient holder for graphite, carbon or metal elect,rodes up to 14in. in diameter has often been felt in this laboratory, as none of t’hose commercially available has been found convenient in routine operation. The spring loaded clamp described here has been designed part’icularly for spark and pulsed arc operation and is easily carried in the Hilger de Grarnont st,and. In addition to its simplicity, t’hree points in the design are worth emphasizing: spring loading 5 permits rapid change of electrode ; as the 7q electrode can be inserted from the open end of the clamp there is no contamina3 tion of either end; the clamp can be , readily dismantled and assembled. \r The arms (1) and (2) of the clamp are 6 of mild steel 2Q in. by 4 in. by $ in., with b f grooves, i:in. deep and 90” included angle. 9’ , _I for posit,ioning the fulcrum (3), whilst (1) 7ff has a similar groove (4) to position the / electrode. The fulcrum (3) can either be 2’ a 2 in. by 3 in. dowel pin as shown, or Fig. 1. Spring loaded electrode clamp-unit to carry upper electrode. can have shoulders to prevent vertical displacement of the arms. At the jaws the height is reduced to 14 in. to facilitate t’he employment of short electrodes, whilst the arms are slotted at the other end to clear the spring, and Tufnol* finger knobs (5) for opening the clamp, are fitted into these slots and held by 1i in. dowel pins (7). At the knob ends the arms are filed on the inside surfaces until a, $ in. diameter rod can just, be introduced laterally into the jaws. The pillar (S), h in. by 14 in., for holding the clamp in a Hilger type arc stand is screwed into arm (1). The spring (9) is a single coil cut from a one inch diameter 14 SWG steel spring, and displacement is prevented by small depressions (10) in the arms 4 in. from the fulcrum. These springs are easily renewed should they lose their tension and any required tension can be obtained either by changing t’he position of the depressions relative to the fulcrum, or by using a different thickness of wire. The heating of the spring from contact with the arms is slight, since the only direct’ points of contact are at the ends of the coil. The construction is simple, the end of the supporting pillar being the only screwed part. It might appear feasible to use the fulcrum, somewhat lengthened, as the pillar, but experience has shown this to be undesirable.
-“\g!_:;
* A reinforce plastic insulating material. 472