PNP-Railways

21" Hg. Normal Working Vacuum Ejector

The range of Standard Vacuum Brake Ejectors has been evolved following considerable experimentation to provide a reliable and effective means of creating vacuum on steam locomotives for powering brake systems fitted to 71⁄4" & 5" gauge rolling stock. Please note that these ejectors are designed to produce 21”Hg. but most miniature railways run their brake systems at 15”Hg.

The Ejector performance has been optimised to achieve the following:

Create 21" Hg. Vacuum over a normal working range between 70 - 80 p.s.i using reasonably dry saturated steam.

The minimum boiler pressure required to create 21" Hg. to be about 35 p.s.i.

The ejector to maintain this level of vacuum up to 120 p.s.i.

The rate of air ejection to be capable of exhausting a brake system appropriate to the size of the locomotive.

Low steam consumption. The demands for steam to be as low as practicable and in proportion to the locomotives grate area.

The air clack to remain tight over long periods without maintenance.

If a larger than optimal size ejector is fitted, this is not likely to affect performance but will result in greater steam consumption and provide higher evacuation rates.

PNP Railways are able to supply an ejector suitable for a grate area of 30 - 60 in.