March_1968 — Page 43

materials and equipment

VENTILATOR

Automatic Closing When Rain Begins

A CONTROL device which electronic- ally shuts a ventilator the montent rain begins to fall and opens the ven- tilator again only when the rain stops, has been developed by Colt Ventila- tion & Heating Ltd., Surbiton, Surrey. UK.

Ventilators which open a roof completely to allow maximum heat release can now be used in works such as potteries and glassworks which require a great deal of ventila- tion yet cannot tolerate the slightest entry of rain. One device is suffici- ent to operate an entire factory ven- tilation scheme.

The control consists of two units a detector head and a small control box, both of which incorporate elec- trical circuits using solid-state com- ponents. The detector head is mount- ed on the roof in an exposed position: the rain-sensing device, which con- sists of a printed open-circuit network of electro-plated connectors on an epoxy-glass base, being fitted to the top of the detector head casing.

When a drop of rain falls on the face of the detector, an electrical cir- cuit is completed, and a relay oper- ates the switches of the control cir- cuit to close the ventilators immedi- ately. When the rain stops, any water on the detector face is driven off by a thermostatically controlled 15 watt heater and the ventilators open again: the heater also melts any snow or ice

!

Rain sensing device on a test rig

Far East Architect & Builder March, 1968

which might otherwise cover the detector and prevent its efficient oper- ation. Indicator lamps on the control box show when the unit is switched on and when the ventilators are open. Agents are Sime Darby Holdings Ltd., Singapore.

SITE COMMUNICATION

System Operates Over a Light Beam

A

SPEECH Communications system with no wires, which operates over a light beam without the use of a radio frequency is to be marketed by an English company. It is designed for use on construction sites where it is not practical to have a conventional wire link.

The system uses a modulated light beam which can transmit speech over

AEI site communication system

a line of sight path up to a distance of one mile. It incorporates two hand sets as well as transmit and receive units. Included in the system is an infra-red filter which makes the light- beam invisible and maintains per- formance in adverse weather condi- tions.

The beam is transmitted by a lamp which is modulated by a speech signal via solid state circuits working from four 11⁄2 volt batteries. The light- weight portable system can be moved from site to site, and be set up and operating within minutes.

Advantages of the light-beam phone include easy movement and elimina- tion of installation costs. The installa- tion process only involves the lining up of the two transmit and receive units which is further simplified by using built-in telescopic view finders for accurate alignment.

Further information is available from AEI Control Equipment Division, Leicester. UK.

LIGHT FITTING

Moisture-proof Unit for Indoo.s or Outdoors

THE Day-Brite Division of Emerson Electric Co., 5411 Bulwer, St. Louis, Mo., USA, has produced an all-plastic luminaire, the Vaporlume II, for use in areas where moisture and dust are present.

It has a thermoplastic housing and captive latches. A continuous neoprene

Vaporlume luminaire

gasket joins the one-piece injection- molded housing and the acrylic en- closure. Captive latches maintain a positive seal and make the unit com- pletely non-conductive and suitable for wash-down maintenance,

The fixture uses one or two 4 ft. lamps. It measures 4% in. deep, 71⁄2 in. wide and can be surface mounted or suspended. Further in- formation is available from the mak-

ers.

Agents are Connell Bros. Co. Ltd.. Singapore, Hong Kong. Rizal and Bangkok: and Tong Hsing Enterprise Co. Ltd.. Taipei.

FILING SYSTEM

Compact Card Holders

Can Be Handled Like Books

THE compact, easily-operated Vista- fan visible-card record system makes use of specially-designed card holders and matching filing trays. Equipped with a heavy cardboard cover, each holder has a capacity of up to 50 double-folded removable cards and can be held open in the hand like a book; each grey-plastic filing tray will store up to nine of these holders.

Both the card holders and the filing trays come in two sizes for A5- and A6-size cards. Overall dimensions of the A5 tray are 83⁄4 in. high by 1 ft. 1% in. long, while the A6 version measures 61⁄2 in. wide by

Anson Vistafan record system

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