Multi-stage blow-pipe construction

Claim 1

In a pulse-jet dust dust collector wherein a plurality of elongate open ended filter socks are simultaneously subjected to cleaning by the abrupt emission of short duration jet pulses of cleaning gas selectively directed into the open ends thereof, the improvement comprising terminally sealed elongate hollow blow-pipe means connected to a remote source of pressurized cleaning gas through a quick acting valve and having a plurality of selectively located apertures therein for effecting the delivery of said selectively directed pulses of said cleaning gas therefrom into the open ends of said filter socks upon actuation of said valve to effect cleaning thereof, and means defining an internal gas impervious restriction at about the mid length of said blow pipe means extending inwardly from the internal defining wall of said blow pipe and disposed substantially perpendicular to the direction of flow of cleaning fluid within said blow-pipe means to abruptly reduce the cross-sectional area of said blow-pipe means available for cleaning gas flow therethrough and to increase the rate of emission of cleaning gas from said apertures disposed adjacent to said valve.