New Air Compressors
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of a well-known make
The Latest Product to be Marketed by the Maker of Ingersoll-Rand Appliances
vrODERN garages and service stations require corn
pressed air for a multiplicity of purposes. In some cases the plant is fixed and pipe lines run to various points, whilst in Others it is more convenient to use the plant on a trolley as a mobile outfit. To meet both., these demands. Ingersoll-Rand Co., Ltd., 165, Queen Victoria Street, London, E.C.4, has brought out the type 30 compressor. As one instance of its utility a giant pneumatic tyre can be inflated from flat to 100 lb. in 1 minute to 11 minute.
The cylindrical receiver is either bolted down to the bed or mounted upon castor wheels. Above the air vessel is the baseboard carrying the electric motor, pressure regulator, gauge and compressor. The ball-bearing motor drives the compressor through V-section belting; the spokes of the flywheel form fan blades, directing an air stream on to the cylinders and inter-cooler.
Two-stage conamession is employed; this is generally regarded as the most efficient system when pressures up to 200 lb. per sq. in. are required. Air is drawn into the larger cylinder through a silencer and passes, after initial compression, tthrough the copper-tube inter-cooler to the second cylinder. Inlet and outlet in both cylinders are regulated by plate-type valves. The air-cooled cylinders have bores honed to fine limits of accuracy, and there are two scraper rings per piston, se that oil should be kept out of the piping. Standard equipment includes an automatic stopping and starting device; this means that the motor runs only when the pressure falls below a predetermined amount. This, of course, saves power costs. Another interesting fitment is the automatictunloader. So soon as the compressor stops air is released from the cylinders. In consequence, when the motor is switched on next time there is no load against which to starts