materials and
equipment
STRUCTURAL MODELS
A modelling kit called the EMA pre- liminary structural system is designed to aid the structural arrangement and layout of plant in industrial design.
It provides a means for "three di- mensional sketches" of proposed ar- rangements that can be quickly altered or revised. Column spacing and beam elevations and locations can be changed without tools.
The plastic components are acc- urately injection moulded and, while they do not represent actual structural
EMA structural system
sizes, they are designed for scales com- monly used in industrial plant design.
The makers are Engineering Model Associates, 1621 N. Indiana Street, Los Angeles, USA.
CIRCUIT BREAKER
Three versions of the current-oper- ated, earth-leakage circuit breaker, type HO3, trip quickly to provide effective protection against shock and fire.
Both the unfused type HO3/1 and the fused type HO3/2 have a nominal operating time of 25 milli-sec. on a 500-milli-amp tripping current, while the extra-sensitive type HO3/3 has an equally fast operating speed on a trip- ping current of 25-30 milli-amp.
Each model measures 169 x 53 x 96 mm. overall, and is simple in operation. An equal current is carried by each winding in the core balance
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Type H03/1 circuit breaker
of the transformer and the reed relay remains inoperative until a current is generated on the trip-coil. Should an earth develop however, the current in one coil of the transformer is reduced accordingly; the transformer is thrown out of balance and a flux set up in the core which is detected by the trip coil. This energises the reed relay, complet- ing the shunt trip-coil circuit and trip- ping the breaker.
A test button on all three models simulates a leakage of current. Switch- ing capacity is 600 amps. and the through capacity is 3,000 amps.
The makers are B & R Relays Ltd., Temple Fields, Harlow, Essex, UK.
ANCHORAGE SYSTEM
head is then contracted and the borer withdrawn.
A tension member is then inserted in the hole. This member can be either a strand cable or a bar; the end anchorage of the cable is a swaged ferrule, while the anchorage on the bar is a plate. Cement or resin grout is used for grout compound and can be placed either before or after inser- tion of the tension member.
FLOODLIGHTS
Weatherproof temporary flood lighting for small, medium or large areas is provided by three series of GM Trilite tripod-mounted floods. These are the SIT 120, 130 and 140, and the GM Standlite SIT 150, which may be self-standing or tripod mounted. Outputs range from 150 to 1,500W for either 110 or 240V working.
The four types of SIT 120 Trilite are intended for small-scale flood light- ing and are fitted with one, two, three or four 150W tungsten lamps. The 130
A system for anchoring bridges, SIT 140 tripod-mounted floodlight
foundations and structures to the rock or cohesive strata on which they are built has been developed by Universal Anchorage Co. Ltd., Westhoughton, Lancs., UK. It can also be used to straighten and reinforce bulging or col- lapsing walls.
A hole is drilled into the rock and when the correct depth is achieved the
Solid grout cones
cutting head of the borer is expanded gradually so that it gouges out a cone- shaped cavity at the end of the hole. This cavity can be up to four times wider than the hole itself. The cutting
and 140 models have tungsten-halogen lamps which are said to combine a 15 per cent. higher output than the ordin- ary tungsten type with a longer life.
The makers are Gardiner Marshall Engineering Ltd., 7 Cambridge Park, Bristol 6, UK.
NON-STICK FABRIC
A new type of PTFE (polytetra fluoroethylene)-coated glass fabric, impregnated with graphite, has been developed by the Tygadure Division of Fothergill & Harvey Ltd., Littlebo- rough, Lancs., UK. When applied to surfaces subject to rubbing or sliding it prevents any build-up of static elec- tricity.
The material combines the strength and dimensional stability of glass-fibre with the low-friction, non-stick surface properties of PTFE. It is non-toxic, has a working temperature range from
Far East BUILDER, December 1968
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