Modern Methods in our Workshops

(By S. B. Barltrop, Production Draughtsman, Hillside.)

The air compressors used in most of the Railway Workshops prior to the reorganisation were steam-driven, and ran at a speed of from 90 to 100 revolutions per minute. These compressors were only large enough to supply a very limited number of pneumatic tools throughout the shops. Thus difficulty was not infrequently experienced in maintaining the necessary air pressure to enable the pneumatic drills, chippers, riveters, hoists and grinders to be worked at the maximum capacity. (One of these steam-driven compressors is shown in the illustration marked No. 1.)

With the coming of the new order in the Workshops and the introduction of modern pneumatic appliances, it was found necessary to instal electrically-driven high-speed compressors, running at a speed up to 300 revolutions per minute. A typical installation is shewn in illustration No. 2, which features a 100 h.p. motor coupled to an air compressor with Lennix short centre drive. The compressor has a capacity of 650 cubic feet of free air per minute.

The quality of the air to be supplied to the air tools is an important factor in their efficient operation. The air should be free from all impurities and moisture. Damp air, or air laden with dust, causes considerable trouble in service pipes, and additional wear and tear on the pneumatic tools. Ordinary free air entering the inlet of a compressor always contains moisture in the

Air Compressors Old And New.
(1.) Steam-driven air compressor (capacity 600 cubic feet per minute) at the old Workshops at Hillside.
(2.) Modern electrically-driven air compressor (capacity 650 cubic feet per minute) recently installed at Hillside.

form of the invisible vapour of water—the amount of water being governed by the percentage of humidity of the air at any temperature. In order that this moisture may be eliminated, an “after-cooler” consisting of a vertical receiver fitted with water-cooled tubes, is provided. This “after-cooler” after receiving the air from the compressor, reduces the temperature to normal, and the dirt and water are precipitated and drawn off, so that only clean dry air is passed through the service pipes to the operating tools.

Another great improvement affecting the supply of air has been the replacement of the old, small bore, service pipes with large pipes designed to deliver air to every part of the shops at a definite and maintained pressure with a minimum of pipe line friction, thus enabling all tools to be worked at their maximum efficiency. By virtue of these modern pneumatic installations much laborious manual work has been eliminated.

Work that had formerly to be done by hand can be more expeditiously performed by the use of power-driven tools. The use of compressed air and pneumatically operated appliances has proved to be a convenient and effective method of providing a flexible supply of power to portable machines, thus effecting a considerable saving in workshop operations.

“… Where the everlasting hills Open their rocky gates to let thee pass, Child of a thousand rapid running rills.”
—Frances Anne Kemble.
A party of tourists in the Tongariro National Park, North Island, New Zealand. (Reached from National Park Station on the Main Trunk Line.)

“Its brilliant hues with all their beams unshorn, Resembling, ‘mid the torture of the scene, Love watching Madness with unalterable mein.”
—Ryron.
A party of Railway excursionists at the foot of the famous Hochstetter Ice Falls, (flowing two miles wide into the Tasman Glacier), Southern Alps, South Island, New Zealand.